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- Front Matter: Volume 7136
- Network Elements I
- Nonlinear Optics
- Advanced Networks
- Modulation Formats
- Best Student Papers
- Optical Monitoring and Compensation I
- OCDMA
- Signal Theory
- Transmission Systems
- Optical Signal Processing I
- RoF and Wireless Networks I
- 100 Gbps Systems
- Access Networks
- OXC, ROADM, and Switching Elements
- Advanced Research Trends
- Dispersion and PMD compensation
- Electronic Processing
- Network Elements II
- Light Generators
- WDM Transmission and Modulation Formats
- RoF and Wireless Networks II
- Optical Signal Processing II
- High-speed Transmission Systems
- Optical Monitoring and Compensation II
- Poster Session
Front Matter: Volume 7136
Front Matter: Volume 7136
Show abstract
This PDF file contains the front matter associated with SPIE
Proceedings Volume 7136, including the Title Page, Copyright
information, Table of Contents, Introduction (if any), and the
Conference Committee listing.
Network Elements I
10GHz all-optical packet clock recovery with ultrafast locking and unlocking time via XPM effect of the SOA
Show abstract
Short locking and unlocking time is essepecially important in the packet clock recovery, as it determines the network
resource utilization. This paper presents a novel 10-GHz all-optical packet clock extractor with ultrafast locking and
unlocking time via self-phase modulation (SPM) effect of the semiconductor optical amplifier (SOA). Low finesse
Fabry-Perot (F-P) filter and a saturated SOA, in cascade, are used to directly extract the packet clock from the data
stream. An optical bandpass filter(OBPF) is used to filter out the red-shifted parts of the packet clock in order to reduce
the locking and unlocking time. We analytically investigate the impact of the locking and unlocking time thanks to the
self-gain modulation (SGM) effect and self-phase modulation(SPM) effect induced by the SOA, and demonstrate 10GHz
clock extraction with the establishing time of 200ps and vanishing time of 600ps experimentally.
40Gbps parallel optical module based on an advanced structure of optical coupling
Show abstract
We propose an advanced structure of optical coupling which realizes high coupling efficiency and simplifying
alignment, enabling the application of optical interconnect. A high-efficiency optical transmitter module based on this
advanced coupling was fabricated using a VCSEL array. The VCSEL was directly bonded on bracket which is pasted on
a holder with two pin used to locate. And there is a dummy club at the middle of the package for laser driver, favorable
for cooling and reducing the noise caused by ground return. Coupling component were fabricated. And bending loss was
tested. A successful eye diagram at the speed of 3.3Gb/s/ch with 850 nm was accomplished from the VCSEL-directbonded
transmitter module.
Tunable and reconfigurable microwave photonic filter implemented by cascaded Mach-Zehnder modulators and a dispersive medium
Show abstract
A novel tunable and reconfigurable microwave photonic filter based on two cascaded Mach-Zehnder modulators (MZMs)
and a dispersive medium is presented, theoretically discussed and experimentally demonstrated. A single-wavelength
laser diode (LD) and the first MZM are used to obtain a multi-wavelength optical source, and the second MZM is
modulated with the signal to be processed. The dispersive medium provides the time delay for different taps, since
different wavelength experiences different time delay, when it travels in the optical fiber. By adjusting the modulation
frequency and the bias voltage on the first MZM, the wavelength spacing and the relative amplitude of the optical tones
after the first MZM can be changed, thus making the filter tunable and reconfigurable. The presented microwave
photonic filter has been implemented in the experiment. The experimental results agree well with the simulation results,
and show that the present microwave photonic filter has good tunability and reconfigurability. The mainlobe-to-sidelobe
ratio (MSR) of around 25dB is achieved for the presented filter in the experiment.
Mitigation of patterning effect in wavelength conversion by cascaded semiconductor optical amplifier and electroabsorption modulator
Show abstract
A scheme for mitigating patterning effects in wavelength conversion by using a concatenated semiconductor optical
amplifier (SOA) and electroabsorption modulator (EAM) is proposed. The scheme is investigated theoretically and
experimentally. The bit error ratio and the power penalty of the converted output signal are estimated and compared with
the results of wavelength conversion based on cross gain modulation in a single SOA.
Nonlinear Optics
Dispersion induced RF power degradation in optical true time delay implemented by broadband light source and a dispersion element
Show abstract
Dispersion-induced radio-frequency (RF) power degradation in the optical true time delay (OTTD) module implemented
by a broadband light source (BBLS) and a dispersion element is studied in this paper, both theoretically and
experimentally. Theoretical results indicate that compared with that using a tunable laser source (TLS), OTTD using a
BBLS suffers from extra power degradation, and that when the transfer function of the tunable optical filter (TOF) can
be approximated to be rectangular, at additional frequencies besides the power-vanishing frequencies in the case of using
TLS, the phenomenon of electrical power-vanishing can also be observed. Experiments using a TLS and a BBLS are
performed for comparison, and TOFs of different bandwidth are used. The electrical transfer functions are measured and
prove the conclusion of the theory. The electrical power-vanishing frequencies are provided and in good agreement with
the theoretical values.
Pulse delay and advancement in ring resonator with mutual modes coupling
Show abstract
We show that a ring resonator with mutual modes coupling can achieve pulse delay or advancement of tens nanoseconds,
which is similar as a ring resonator with single mode. Nevertheless, the pulse response can be sensitively
tunable either through mutual mode coupling or through waveguide-ring coupling in the vicinity of resonant frequency.
Effects of loss and dispersion on fiber-based quantum key distribution system
Show abstract
Studied are the effects of fiber dispersion and loss and single-photon detector dark counts on key transmission rate and
bit error rate of quantum key distribution system through theoretical analysis and computation. Research demonstrates
that fiber loss is the main factor that influences quantum key transmission rate, while quantum bit error rate is related to
fiber loss, dispersion, pulse width, dark counts and Rayleigh backscattering. Theoretical calculation indicates that in the
current single-mode fiber-based plug & play quantum key distribution system with a dark counts of 10 -5/ns, the
utilization of short pulse with 1550 nm wavelength and a 50 ps width can achieve the maximum transmission distance of
131 km. If we reduce dark counts or use G.653 dispersion-shifted fiber with short pulse, we can further improve key
transmission rate and reduce the quantum bit error rate, thus effectively enhance the transmission distance of quantum
key distribution system.
All-optical frequency up-conversion and demultiplexing with a fiber-ring-based microwave photonic filter in an IM-DD radio-over-fiber system
Show abstract
In this paper, the authors present and experimentally demonstrate an all-optical frequency up-conversion and
demultiplexing method in a radio-over-fiber (RoF) system. A Mach-Zehnder modulator (MZM) and a microwave
photonic filter based on a fiber ring structure are used to simultaneously realize the frequency up-conversion and
demultiplexing functions. In this proposed system, only a fiber ring and a photodiode (PD) are needed in the base station
(BS) to fulfill the signal processing functions. This simple solution makes the base stations more cost-effective, and
shows good application potential in the future radio-over-fiber systems.
Advanced Networks
A hybrid analytic model of burst loss probability in optical burst switching networks
Show abstract
In this paper, the different properties of bursts of bypass traffic and bursts of local adding traffic were emphasized in
Optical Burst Switching (OBS) networks. Based on this phenomenon, a hybrid analytic model of burst loss probability
was developed. The simulation results show that our model is more accurate than the previous models.
Analysis of wavelength conversion in OBS scheduling algorithm
Show abstract
A wavelength scheduling algorithm with limited-range wavelength conversion in OBS network is presented in this
paper. Two wavelength conversion policies, First-Fit (FF) and Nearest Wavelength First (NWF) are adopted respectively
in this scheduling algorithm. Numerical results show that the FF and NWF perform nearly identical in the scenarios of
sparse wavelengths with small conversion range and large wavelengths with small conversion range. The FF outperforms
NWF when the wavelength number is large and the conversion range is wide. However, consider the fact that output
power strongly deteriorates as a function of the distance between the ingoing and outgoing wavelengths, the NWF policy
should be adopted in the practical OBS networks.
Modulation Formats
DPSK-3ASK transmission optimization by adapting modulation levels
Show abstract
For metro and regional 100-Gbps transmission, a transparent channel reach of 500-600 km is required and a 100-GHz
channel grid is typically used. For these applications, a cost effective modulation format is introduced which can make
use of electronic components designed for the already established 40-Gbps market, bypassing the requirements for novel
electronic developments and therefore reducing the component cost. With this DPSK-3ASK modulation format, five
information bits are transmitted in two consecutive symbols, leading to a symbol rate of 45 Gbaud, including overhead
for framing and FEC. To minimize hardware requirements and to create a cost-effective solution, a single Mach-Zehnder
modulator can be used to create the optical DPSK-3ASK signal after combining the phase and amplitude modulation
signals into a 6-level modulator drive voltage. In this paper, it is demonstrated by numerical simulations that these
voltage levels can be modified to adapt to varying signal distortions and thereby yield improved transmission
performance. It is shown that by dynamically modifying the modulation levels based on the channel performance,
dynamic signal impairments such as the non-linear effects from varying power levels, changes in chromatic dispersion,
or varying PMD levels can be mitigated. Error-free performance (with FEC) can be obtained with 24 dB OSNR and 7ps
DGD for a 112-Gbps (45-Gbaud) optical signal.
Advanced modulation and coding technologies for ultra-high-speed optical communications
Show abstract
We introduce two important technologies for development of next generation ultra-high-speed optical communications:
(i) polarization multiplexing, phase modulation with digital coherent detection, and (ii) OFDM-based optical fiber
transmission. In both schemes, digital signal processing plays a key role in recovering the signal and mitigating the
detrimental effects from optical signal transmission. We further describe a novel three dimensional low-density parity
check (LDPC) coded modulation scheme, including its principle and system performance.
A novel optical DPSK/PolSK orthogonal encoding method for all-optical label swapping
Show abstract
A novel approach for optical DPSK/PolSK orthogonal encoding based on four-wave mixing effect in a semiconductor
optical amplifier is proposed and tested using VPI simulation platform. The combined DPSK/PolSK signal is
successfully generated and demodulated with clear and open eyes.
The study of optical FSK modulation for 40-Gb/s WDM-PON network with centralized lightwave source
Show abstract
This paper proposes and numerically investigated a novel high-speed wavelength-division-multiplexed passive optical
network (WDM-PON) architecture with colorless user terminals based on the use of a different modulation scheme for
downstream and upstream transmission. In the central office (CO), based on the carrier suppressing functionality of
Mach-Zehnder modulator (MZM) and differential-phase-shift-keying to amplitude-shift-keying conversion using
Mach-Zehnder delay interferometer, 40-Gb/s optical frequency shift keying (FSK) is generated and employed for
transmitting the downstream data. In the remote node (RN) or optical network unit (ONU), the upstream data is
re-modulated at 2.5-Gb/s by an intensity modulator and sent back to CO with the same fiber. Since only one light source
is needed for each WDM channel, and the MZM to generate carrier suppressed signal can be shared by all the channels, a
centralized 40-Gb/s WDM-PON access system with low-cost configuration is realized. Error free transmission over
20-km SMF can be observed for both downstream and upstream signals in our simulation.
Phase regeneration of DPSK/DQPSK signals based on phase-sensitive amplification
Show abstract
Nonlinear Mach-Zehnder interferometers, when driven by a phase-locked local oscillator pump, provide phase-sensitive
amplification to input signals. So phase-sensitive amplifier(PSA) can be used to realize phase regeneration of phase
modulated signals. In the paper, we adopt kerr media-based nonlinear Mach-Zehnder interferometer to form a PSA to
regenerate DPSK signals, and we propose a structure for the phase regenerating of DQPSK signals using two balanced
PSAs. Theoretical analyses of all-optical phase regenerations of DPSK/DQPSK signals based on phase-sensitive
amplification are presented. Simulations show that nearly ideal phase regeneration can be achieved for the
DPSK/DQPSK signals.
Best Student Papers
High reflection tolerance of 1.25-Gb/s RSOA-based WDM PON employing spectrum-sliced ASE source
Show abstract
We investigate the impact of the reflection in an RSOA-based WDM PON utilizing the spectrum-sliced ASE source as
the seed light. Since the spectrum-sliced ASE source has sufficiently large bandwidth to suppress the optical beat
interference (OBI) noise, we can achieve the high reflection tolerance in comparison with that in a conventional WDM
PON using the remodulation scheme. In the experiment, we systematically investigate the dependence of the reflection
tolerance on the operating conditions such as the optical power and bandwidth of the spectrum-sliced ASE source
injected into the RSOA. In the case when the injection power into the RSOA is low, the performance of the upstream
signal becomes vulnerable due to the reflection-induced incoherent crosstalk and parasitic laser oscillation. However, we
can improve the reflection tolerance significantly by increasing the optical power and the bandwidth of the spectrumsliced
ASE source. By optimizing these operating conditions, we can achieve an excellent refection tolerance greater
than -15 dB.
Generation and transmission of 86 Gbit/s hybrid polarization-division multiplexed OOK/DPSK signal
Show abstract
86 Gbit/s hybrid polarization multiplexed OOK/DPSK signal is generated and transmitted at the
same wavelength. Clear eye diagrams of demultiplexed OOK and DPSK signals are obtained after
transmission over a 106.5 km SSMF fiber span.
Comparison of the three schemes to generate optical mm-wave signal and wavelength reuse for upstream connection in the radio-over-fiber systems
Ze Dong,
Yazi Pi,
Jia Lu,
et al.
Show abstract
Three different schemes to generate optical millimeter-wave and wavelength reuse for up-link connection in the radioover-
fiber (ROF) systems have been theoretically and experimentally investigated. We have compared the performance
of the three different schemes for the radio-over-fiber systems considering the cost and configuration of their
architectures. A novel scheme to generate optical millimeter-wave and realize centralize lightwave operation in the
radio-over-fiber (ROF) systems has been demonstrated. This scheme has shown high performance and low cost
compared with the existing schemes.
16 DWDM channels optoelectronic 3R NRZ-to-RZ regenerative format conversions based on single phase modulator
Show abstract
We propose and demonstrate simultaneous multiple dense wavelength division multiplexing (DWDM) channels
optoelectronic non-return-to-zero (NRZ) to return-to-zero (RZ) regenerative format conversions based on a single phase
modulator (PM) and a fibre delay-interferometer (DI). The PM is driven by a local RF clock signal, and the DI with free
spectral range (FSR) equals to the channel spacing is used to extract the chirps induced by the phase modulation, for all
the channels at the same time. Since the original carriers are suppressed to some extent while the chirps are extracted,
thus the NRZ-to-RZ conversions can be achieved with regeneration. The proposed multi-channels format conversions are
successfully demonstrated at 16*10 Gb/s, with channel spacing of 100GHz. Bit error ratio (BER) measurements show
3.5 and 4.2 dB penalty improvements for 50 and 75 km transmission without dispersion compensation, respectively.
8×10 Gb/s data packets buffered in Dual Loop Optical Buffer (DLOB)
Show abstract
Abstract-We demonstrated 8 × 10 Gbit/s packets buffered in Dual Loop Optical
Buffer (DLOB).Confirmed by experiments, the crosstalk and unbalanced power
among different wavelengths which is the main restraining of the buffering time can
be avoided by power equalization using Semiconductor Optical Amplifier (SOA). The
buffered data packets can be retrieved after they are buffered for 5 cycles. The power
penalty, the Extinction Ratio and the Signal to Noise Ratio are 4.2dB, 3.98dB, 5.47dB.
The eye diagrams for 8 wavelengths signals are obtained.
Simultaneous transmission of high-speed point-to-point data and double broadcast services in a WDM-PON system with source-free ONUs
Show abstract
We propose that double broadcast services can be overlaid over high-speed point-to-point downlink data in a WDMPON
with source-free optical network units (ONUs). In the optical line terminal (OLT), a set of single-drive Mach-
Zehnder modulators (MZMs) are driven by downlink point-to-point data to generate a differential phase-shift keying
(DPSK) format. The downlink DPSK signals from different wavelengths are multiplexed and then fed to a following
dual-parallel MZM (DPMZM) as a double broadcast services transmitter. The broadcast service_1 is an optical carrier
suppression (OCS) format, while the broadcast service_2 is an inverse return-to-zero (IRZ) forma. After the transmission,
at each ONU, the optical signals are separated by an optical filter. The filtered OCS signal is detected to retrieve the
broadcast service_1. The DPSK/IRZ signals are split into three parts, one part is detected by an IRZ receiver to recover
the broadcast service_2, the second part is detected by a DPSK receiver to retrieve the downlink data and the third part is
re-modulated by the upstream amplitude shift keying (ASK). We also perform an experiment to verify the feasibility of
the proposed scheme, where the power penalties of less than 1.5 dB are obtained after 25-km transmission with 1.25-
Gb/s data rate.
Optical Monitoring and Compensation I
Enhancing PMD monitoring and compensation for DPSK and DQPSK signals using variable DGD modules
Show abstract
Facilitated by variable differential-group-delay (DGD) modules, we propose a simple method to extend polarizationmode-
dispersion (PMD) monitoring windows three times larger using either degree-of-polarization (DOP) for 40-Gbaud
differential-phase-shifted-keying (DPSK) differential-quadrature-phase-shifted-keying (DQPSK) signals. Such approach
can be further incorporated into PMD compensators.
Monitoring techniques for phase and OSNR of DPSK/DQPSK signals
Show abstract
We review our recent achievements in the optical performance monitoring techniques such as the optical phasor
monitor and optical signal-to-noise ratio (OSNR) monitor developed for differential phase-shift-keyed (DPSK) and
quaternary PSK (DQPSK) signals. The optical phasor monitor is a tool that can measure the in-phase and quadrature
components of the optical field of the phase-modulated signal and display the measured results on the complex plane as a
phasor. We implement such a phasor monitor by using an adjustment-free differential-phase demodulator composed of a
120-degree optical hybrid (which can be realized simply by using a conventional 3x3 optical coupler), and demonstrate
its plug-and-play (i.e., phase-adjustment free and wavelength/polarization-independent) operation experimentally. We
also show that the proposed phasor monitor is well suited for the use in the diagnosis of DPSK/DQPSK. The OSNR
monitoring is another important function to evaluate the signal quality as well as the condition of the transmission link.
We have recently proposed a new technique for monitoring the 'in-band' OSNR of DPSK/DQPSK signals. This
technique estimates the OSNR by analyzing the radio frequency (RF) spectrum obtained by the self-heterodyne detection.
In this paper, we briefly explain its operating principle and show the experimental results. Using this technique, we
could accurately monitor the OSNR of the 10-Gb/s DPSK and 20-Gb/s DQPSK signals in a 640-km long transmission
link. The results also show that the performance of the proposed technique is not sensitive to the effects of chromatic
dispersion and polarization-mode dispersion.
A high sensitive wavelength stability monitoring method using 90o optical hybrid
Show abstract
Coherent detection is a new attractive detection method in optical transmission, especially in high capacity long-haul
fiber communication systems. Most coherent detection systems use a local laser as the local oscillator rather than using
an optical phase-locked loop (OPLL). In this case, the signal and local laser's wavelength must be as close as possible,
and both should be stable. Wavelength stability of DFB laser is a critical factor for optical coherent detection and other
applications. We use fiber couplers and a fiber phase shifter to buildup an optical 90o optical hybrid, by which the
wavelength fluctuation is monitored with a very high sensitivity.
Ultra-high speed sampling optical techniques
Show abstract
The main techniques for high bandwidth optical digital sampling are briefed. Potentialities and drawbacks of
optical solutions are investigated and compared.
OCDMA
Impact of the unipolar family codes on the performances of the DS-OCDMA system
Show abstract
This paper presents the Direct Sequence Optical Code Division Multiple Access (DS-OCDMA) system using two
configurations of the optical source. To encode/decode transmitted data, we used Superstructured Fiber Bragg Grating
(S-FBG) as encoders/decoders. We consider three unipolar family codes which are the Prime Sequence (PS), Quadratic
Congruence (QC) and the Extended Quadratic Codes (EQC) codes. In order to evaluate the performances of our system
in term of Bit Error Rate (BER), we implement the Importance Sampling (IS) technique, which is a variant of the wellknown
Monte-Carlo (MC) method. Our simulation results depict that EQC codes outperform QC and PS codes for the
DS-OCDMA system using either coherent or incoherent source. We show also that using EQC codes with increasing the
optical bandwidth and maintaining the electrical filter leads to improve the performance of incoherent system.
Experimental demonstration of a hybrid 1/2-dimensional en/decoding optical code division multiple access system
Show abstract
A hybrid 1D/2D en/decoding O-CDMA system is proposed to support multiple bit rates. To the best of our knowledge, a
hybrid O-CDMA system with 2.5Gb/s (OC-16) and 155Mb/s (OC-3) transmission along the single mode fiber with
length of 60km is first successfully demonstrated. In this experimental demonstration, phase coded SSFBGs with chip
rate up to 320Gchip/s are applied as 1-dimensional en/decoders in 2.5Gb/s transmission while 2D en/decoders are
applied in 155Mb/s real time video transmission. Error free transmission is achieved in 1D encoded 2.5Gb/s link; while
2D encoded 155Mb/s channel carrying video signal can be transmitted along the same fiber. This proposed hybrid
1D/2D en/decoding O-CDMA system can also be used for O-CDMA PONs to reduce the costs at the ONU side.
Signal Theory
Research on the detection probability of multi-band optical detection system
Show abstract
Different operation models of joint optical multi-band detection systems are provided here, corresponding to the different
characters of detecting probabilities of subsystems. It leads to a higher over-all detecting probability. The joint optical
detection system is able to be operated under different models when detection probabilities of subsystems are low or
there is big difference among the probabilities. When all the probabilities of subsystems are low, the joint optical
detection system directly conducts data fusing. If there is big difference among the probabilities of subsystems,
information from the subsystems is chosen before entering the fusion center. In this way, the false-alarm probability of
the joint optical detection system reduces obviously comparing with direct data fusion. So it also can reduce the
calculation of system and improve the competence of system.
Revisiting binary sequence length requirements to accurately emulate optical transmission systems in highly dispersive regime
Show abstract
When increasing channel bit rate beyond 10Gb/s or when operating over fiber lines with sparse or no in-line dispersion
compensation, Kerr-like non-linear effects can be considered as second order with respect to dispersive effects, because
pulse broadening can expand over numerous neighbor pulses, before optical non-linear effects imprint their signature
noticeably. To accurately emulate the interactions between pulses in this case, a few studies emphasized that Pseudo-
Random Binary Sequences (PRBS) should be used, with exponential dependence of the required PRBS length on bit rate
and accumulated dispersion. In this paper, we explain our strategy to numerically estimate the required number of
random, noisy bits for Monte-Carlo simulations, and show that it weakly increases in presence of pulse to pulse
correlations and commonly tolerated levels of non-linearities (i.e. leading to transmission penalties as high as 1.5dB, for
reference BERs of 10-2, 10-3 or 10-5) . Then we determine the actual required PRBS length that yields the same
(sufficient) BER accuracy as the MC method. We demonstrate its actual dependence on BER, and show that MC theory
provides a reliable upper bound in FEC-assisted, highly dispersive systems.
NLOS single scattering model in digital UV communication
Show abstract
A practical single-scattering model of solar blind UV communication channel, which is suitable for NLOS digital
communication is presented in the paper. NLOS transmission loss of UV channel is deduced by Lambert law .
Calculation method of scattering phase function and integral of intersection volume between transmitting beam and
receiving beam are described detailed in prolate spheriodal coordinate. Base on them, a practicable calculation method
about signal to noise ratio (SNR) and bit error rate (BER) of UV communication systems is presented, which construct a
bridge between system parameters and digital system performances in simulation of UV communication channel and
systems .Under certain BER and typical modulations in UV communication , relationship between system parameters and
system performances are discussed.
The dynamical effects of FWM and XPM on optical pulse propagation under IP traffic in dynamical DWDM networks
Show abstract
In this paper, the influence of the burstiness of IP packets on nonlinear effects in dynamical optical Networks such as
XPM (cross phase modulation) and FWM (four-wave mixing) are investigated and simulated by adding revised Poisson
distributed traffic parameters in the nonlinear Schrödinger equation (NLSE).From simulations, different eye diagrams
with different IP traffic loads, different fiber input light powers are achieved. When the input power is bigger than 3 dBm
with 40 channels or bigger than 5dBm with 16 channels, the effect of IP bursty traffic could depredates eye diagrams
dramatically. The research results are useful for router finding and system design.
Dual wavelength signals buffered in DLOB and its improvement by power equalization
Show abstract
ww have presented and demonstrated the dual-wavelength signal storage in Dual-Loop Optical Buffer. The output equality of dual wavelength signals will decrease for unbalanced gain and phase shift. The problem can be resolved by power equalization using the saturation character of SOA. The data packets with2 × 2.5Gb/s can be buffered in DLOB for 16 cycles corresponding to 20 .The Extinction Ratio of the output packet is 8dB while the S/N is 8.1dB.
Transmission Systems
Effect of laser frequency offset on optical minimum-shift keying transmission system
Show abstract
As a special case of continuous phase frequency-shift-keying (FSK), minimum-shift keying (MSK) exhibits some
different properties compared with the traditional optical phase modulation formats, such as return-to-zero (RZ)
differential-phase-shift-keying (DPSK) and differential-quadrature-phase-shift-keying (DQPSK). In this paper, we
investigated the receiver performance degradation caused by laser frequency offset between laser frequency and delay
interferometer (DI) phase, which is found to be the most critical impairment for the receiver performance in a practical
optical phase modulated system. Results show that MSK system is about double times and six times more robust to
frequency offsets than RZ-DPSK and RZ-DQPSK systems operating at the same 10Gb/s bit rate, respectively.
QAM transmission system based on heterodyne optical detection using intermediate frequency carrier modulation
Show abstract
Compared with the optical communication system using intensity modulation with direct detection (IM-DD), the
coherent optical system enhances the sensitivity and enables access to all the optical characteristics. In this paper, a novel
scheme of coherent QAM transmission system based on heterodyne optical detection is experimentally demonstrated. In
the proposed scheme, the intermediate frequency (IF) carrier modulation at double-sideband suppressed carrier (DSB-SC)
mode at the transmitter side enables demodulation of QAM signal with heterodyne detection. Furthermore, the receiver
is simplified by avoiding the use of high frequency broadband microwave devices due to the employment of IF carrier
modulation. The performance of the proposed coherent QAM system is analyzed theoretically based on numerical
simulation. The simulation results show that the improved structure of the proposed system can effectively depress the
phase noise induced by laser. An experiment of 4-QAM transmission exploiting the proposed coherent heterodyne
system is presented to justify the principle.
A method for optimizing optical duobinary transmission systems
Show abstract
DWDM networks have been evolving to higher spectral efficiency. To make optical duobinary format,
which is considered as a suitable modulation format in MAN DWDM networks, can work in 50GHz
channel spacing 43Gb/s DWDM networks is very significant. In this paper, it is pointed out that the
delay time in delay-and-add optical duobinary system is one of key factors which affect system
performance. The suitable delay time for 43Gb/s systems compatible 50GHz with 100GHz channel
spacing is obtained by system simulation. The simulation results show that 0.8 bit delay time is more
suitable for 43Gb/s ODB DWDM system at compatible 50 with 100GHz channel spacing than 1 bit delay
time because of its higher Q value and bigger dispersion and nonlinearity tolerance.
Performance of optical OFDM system affected by the high peak-to-average power ratio
Show abstract
Within the realm of OFDM research, (peak-to-average power ratio)PAPR is an important object to be considered.
Overlarge PAPR can deteriorate the linearity of the wireless systems. In this paper, we interpret the concept of PAPR in
optical OFDM system and testify that the modulation method in sub-carriers and nonlinear effects can affect PAPR in
the optical OFDM system. Through simulation, PAPR problem stand out while considering OFDM in optical
transmission technology, so reducing it has become an important subject in optical OFDM system.
Optical Signal Processing I
The all-optical flip-flop: state-of-the-art and perspectives
Show abstract
Optical technologies represent the main bet for future communication systems. Among the others, digital subsystems for
optical processing are of great interest thanks to their intrinsic properties in terms of bandwidth, transparency, immunity
to the electromagnetic interference, cost, power consumption, as well as robustness in hostile environment. Key basic
functions are represented by logic gate, logic function, flip-flop memories, optical random access memories, etc..
Research in this field is in its very early stages even if some interesting techniques have been already theoretically
addressed and experimentally demonstrated. In this paper we review the state of the art for all-optical flip-flop including
different approaches such as fiber based, semiconductor amplifier based or waveguide and micro-ring solutions. Best
result will be highlighted in terms of transition speed, switching energy, complexity and power consumption. Finally our
best results are discussed.
High speed wavelength preserved 2R regeneration based on filtering and cross-gain compression in semiconductor optical amplifiers
Show abstract
We propose a novel scheme employing phase to amplitude modulation conversion and cross-gain
compression in Semiconductor Optical Amplifiers (SOAs) to implement 2R regeneration at 40Gb/s.
The resilience on the pumping power and filtering are analyzed.
Performance analysis of an all-optical regenerator for DQPSK/QPSK based on phase-sensitive amplifiers
Show abstract
An all-optical regenerator for Quadrature Phase-Shift Keying (QPSK) and Differential Quadrature Phase-Shift Keying
(DQPSK) signals based on Phase-Sensitive Amplifiers (PSAs) is studied through numerical simulations. It is found that
the regenerator can provide significant suppression of both amplitude and phase noise, and that the BER performance of
the regenerated signals can be greatly improved.
Chromatic dispersion monitoring of DPSK signals using RF power detection
Show abstract
We demonstrate dispersion monitoring of differential phase-shift keying (DPSK) modulated optical transmission system
by measuring RF components of detected optical signal. The results show that this scheme can realize dispersion
monitoring up to 4320ps/nm and sensitivity up to 15.5(ps/nm)/dBm. The effect of OSNR on the performance of the
monitoring system are studied and discussed.
RoF and Wireless Networks I
Wavelength sharing in WDM passive optical networks
Show abstract
Progress towards the definition of next-generation passive optical networks (PONs) based on wavelength-division
multiplexing (WDM) is reviewed and compared to emerging requirements. A key challenge is providing ultra-high (e.g.
10 Gbps) bandwidth for demanding users while cost-effectively supporting less-demanding users. A new approach is
presented in which diverse bandwidth requirements are supported on a conventional WDM PON outside plant through
the use of flexible wavelength sharing in the local office. An example is demonstrated experimentally showing that with
16 users per passive node, each wavelength can be shared by up to 16 users distributed across up to 16 PONs served by
the same local office. Factors limiting sharing and throughput are discussed.
A radio-over-fiber system for simultaneous generation of wired and wireless services
Show abstract
A hybrid optical access configuration for simultaneously providing wired and wireless
services was proposed. The proposed system can also remote deliver doubled local-oscillator
signal, which can be reused in the uplink. At the central station, the signals used for wireless links
are subcarrier multiplexing and modulated as PSK format, and the wired baseband signals are
directly modulated as NRZ format, then two signals are simultaneously generated by an external
integrated modulator and transmitted on the same wavelength. The doubled local-oscillator signal
is extracted in the wireless links, then used in the uplinks, the recieved eye diagrams are pretty
well.
Performance demonstration of 300-km dispersion uncompensated transmission using tunable chirp-managed laser and EDC integratable into small-form-factor MSAs
Show abstract
We demonstrate 300-km transmission of 10Gb/s data over SMF-28 fiber without DCF
using a 4-channel tunable chirp managed laser and EDC chip at the receiver, which can fit into hot
pluggable XFP modules.
100 Gbps Systems
Requirement of modulation bandwidth for 100Gb/s optical DQPSK transmission using one dual-drive Mach Zehnder Modulator
Show abstract
This paper demonstrates bandwidth requirement for optical DPQSK transmitter using one Dual-drive Mach Zehnder
Modulator (DDMZM) for 100Gb/s physical transmission. The result shows that at receiver bandwidth of 40GHz, NRZDQPSK
signal requires 60GHz modulation bandwidth at least, while RZ-DQPSK scheme demands less bandwidth,
about 40GHz for 50% duty cycle RZ-DQPSK signal.
Long-haul 100Gb/s coherent transmission experiments
Show abstract
In this paper, we highlight the potential of Coherent PDM-QPSK format for next-generation 100Gb/s transmission
systems, through a record transmission experiment of 16.4Tb/s over 2550km, and in-depth experimental analyses of
tolerance to joint PMD and non-linear effects, as well as robustness to typical constraints of terrestrial optical networks.
Performance study of a 100-Gb/s transmitter with high tolerance to chromatic dispersion and PMD
Show abstract
A 100-Gb/s high-speed optical transmitter is proposed and experimentally demonstrated. Based on frequencyquadrupling
technique, two sub-channels with a fixed 50-GHz spacing are obtained from one laser source. Using returnto-
zero differential quadrature phase-shift keying (RZ-DQPSK) modulation format and polarization multiplexing
(PolMux), only low-speed electronic devices of 12.5 GHz are needed for the 100-Gb/s transmitter. This eliminates the
need of ultrahigh-speed optoelectronic devices and thus greatly reduces the cost. The experimental results show that this
transmitter can achieve good performance in dispersion tolerance of a 25-km single mode fiber (SMF). The performance
of the generated signal is also verified through simulation with respect to chromatic dispersion (CD), polarization mode
dispersion (PMD) and nonlinearity.
100Gb/s transmission system implementation and optimization
Show abstract
Transmission of eight channel 100Gbit/s CS-RZ DQPSK signals up to 1500km SSMF was demonstrated. This
transmission system only used EDFA and did not adopt coherent detection and polarization multiplexing. The span
spacing in this system varies from 80km to 100km to simulate the practical optical network.
Keywords: Transmission system, modulation format
Access Networks
Generation of multi-service wireless signals on one access point for radio over fiber systems
Show abstract
A novel scheme of one access point with multi-service wireless signals for radio over fiber systems is proposed. The
generation of two 200Mb/s wireless signals with central frequencies at 17.5GHz and 20GHz carried on one optical
wavelength is the preliminary result of the concept-proof experiment.
Implementation of 40Gb/s converter for very short reach optical transmission system
Show abstract
In this paper, a practical 40Gb/s 12:16 converter is implemented for VSR parallel optical transmission.
The converter realizes the functions of mapping OC-768 frame to/from parallel optics. Using two chips
of Altera FPGA and Agilent81250, a complete simplex communication experiment system is built.
Detailed design such as frame synchronization, deskew algorithm and converter are presented. In
addition, we design a SFI-5 interface verifying board to verify the deskew function. Testing results are
also given illustrating that the converter works well.
Experimental demonstration of data remodulation on downstream ASK-DPSK signals for upstream transmission in WDM–PONs
Show abstract
A novel upstream data remodulation scheme with downstream ASK-DPSK modulation format is proposed for WDMPONs
in this letter. And this kind of scheme is also experimentally demonstrated on one particular wavelength channel.
Both the 2.5-Gb/s downstream optical DPSK signal and the 2.5-Gb/s downstream optical ASK signal are demodulated
respectively at the receiving side, while part of the downstream carrier is directly remodulated by an optical intensity
modulator for upstream transmission of 2.5-Gb/s data. System performance under different amplitude ratios of
downstream optical ASK signal is investigated. It is shown that effective reception and robust performance can be
achieved after having been transmitted for 25-km.
Performance analysis of bandwidth limited coherent time spreading OCDMA system employing DPSK format and turbo code
Show abstract
Differential phase shift keying (DPSK) data format is employed to combat noise in the bandwidth limited coherent time spreading (TS) optical code division multiplexing access (OCDMA) system. In addition, the performance of DPSK-OCDMA system with turbo coding is analysed and simulated. Theoretical results show that performance degradation due to bandwidth limitation could be effectively restrained by the DPSK-OCDMA scheme, and further performance improvement could be achieved by incorporating turbo coding into OCDMA system. It is confirmed that the number of active users is increased from K = 11 to K = 25 in bandwidth limited OCDMA system by employing DPSK format and turbo code for a given BER of 10-6.
OXC, ROADM, and Switching Elements
A novel 1xN WSS module based on the MEMS technology
Show abstract
We theoretically and experimentally report a single-wavelength module of 1x4 wavelength selective switch (WSS)
module based on the bi-axial MEMS mirror and thin film filter technology. With a cascaded structure of such WSS
module, a novel 1xN WSS can be realized. The insertion loss of 3dB, extinction ratio > 50dB and hitless switching are
achieved.
Spectrally efficient 3.4b/s/Hz waveband switching over wavelength-selective switch-based ROADM on 114 Gb/s PolMux-RZ-8PSK DWDM system
Show abstract
For the first time, we experimentally investigated and demonstrated waveband switching for 100 Gb/s DWDM system
with high spectral efficiency of 3.4 b/s/Hz. 3 adjacent 25 GHz-spaced 114 Gb/s PolMux-RZ-8PSK channels are grouped
as a waveband to be switched and transmitted through 4 WSS-based ROADM nodes. Error free transmission is achieved
with little filtering effect observed even after 4 ROADM nodes. The transmission performance shows that waveband
switching based on WSS can be used in high spectral efficiency DWDM systems. This can reduce the switching
hardware cost and operation expense in highly dense WDM systems.
All optical switch based on nonlinear polarization rotation (NPR) in semiconductor optical amplifier (SOA)
Show abstract
An all-optical switch is proposed and demonstrated using the nonlinear polarization rotation (NPR) with linear
polarization maintenance arising in a semiconductor optical amplifier (SOA). By introducing optical control pulse into
the SOA, the state of polarization (SOP) of the packet signal can be switched between the vertical linear SOP and the
horizontal linear SOP on the Poicáre sphere (PS). Then a polarization beam splitter (PBS) is used to perform
polarization-to-intensity conversion. Thus the input packet signal can be switched between the two output ports of the
PBS. And an extinction ratio of switching operation larger than 20 dB is obtained.
Advanced Research Trends
Some key technologies for millimeter-wave radio-over-fiber systems based on injection locked lasers
Show abstract
The seamless integration of broadband optical and wireless access networks is considered to be a promising solution for
next generation access networks which will provide high capacity and flexibility with lower cost. In such access
networks millimeter wave (mm-wave) radio over fiber (RoF) system is a key enabling technology due to its its large
bandwidth and short reach in atmosphere. In this paper, we will discuss some key technologies based on injection locked
lasers for mm-wave RoF systems, including all optical generation of mm-wave signal, up- and down-conversion, single
sideband modulation, and transmission.
Stronger slow light effect in densely doped erbium fibers
Show abstract
We perform a study of extremely slow pulse propagation speed in densely-doped erbium fibers
by using a detuned signal. A quantum coherence effect, coherent population oscillations, produces
a very narrow spectral "hole" in the homogeneous broadened absorption profile of the
erbium-doped fiber. The resulting rapid spectral variation of the refractive index leads to a large
value of the group index. The interparticle interaction between the nearest neighboring active
particles due to the high density of erbium ions is considered. The result shows that the nonlinear
refractive index can be greatly increased which leads to the smaller group velocity and the larger
time delay.
Fiber in access technologies and network convergence: an opportunity for optical integration
Show abstract
Broadband networks are among the fastest growing segment in telecom. The initial and still very significant push
originated with xDSL technologies and indeed a significant amount of research and development is still occurring in this
field with impressive results and allowing for a remarkable use of the installed copper infrastructure way beyond its
originally planned bandwidth capabilities. However it is clear that ultimately a more suitable fiber based infrastructure
will be needed in order to reduce both operational and network technology costs. Such cost reduction in inevitable as the
added value to end users is only related to services and these cannot be priced outside a sensible window, whilst the
related bandwidth increase is much more dramatic and its huge variability must be met with little or no cost impact by
the network and its operation. Fiber in access has indeed the potential to cope with a huge bandwidth demand for many
years to come as its inherent bandwidth capabilities are only just tapped by current service requirements. However the
whole technology supply chain must follow in line. In particular optical technology must brace itself to cope with the
required much larger deployment and greater cost effectiveness, whilst at the same time deliver performance suitable to
the bandwidth increase offered in the longer term by the fiber medium. This paper looks at this issues and debates the
opportunities for a new class of optical devices making use of the progress in optical integration
Research forefronts in optical networking
Show abstract
Present-day data networks are being challenged by the relentless growth of bandwidth demand. Most of this future growth, however, is not arising from more users with the same application bandwidth demands, but rather from the dramatic increase in bandwidth demand of emerging applications. The compounding of these two trends has set the stage for optical networking technology to make significant contributions in next-generation data network architecture. In this talk, we will explore key research problems of optical network architecture (such as flow switching) that, if properly exploited, will enable significant growth and cost-effective scalability of next-generation data networks.
Dispersion and PMD compensation
Deterministic first-order and second-order polarization mode dispersion compensator using binary polarization switches
Show abstract
A deterministic first-order and second-order polarization-mode-dispersion (PMD) emulator or compensator using binary
polarization switches is demonstrated. The rotation angles of polarization switches are ±22.5° and are used in pairs
between birefringent elements to provide 0, 45 and 90-degree polarization coupling to generate either first-order (0 and
90-degree) or second-order (45-degree) PMD. We also verify the repeatability of such module for practical applications.
Residual third-order dispersion compensation in femtosecond pulses transmission using a phase modulator
Show abstract
Using the split-step Fourier method, the nonlinear effects and higher-order dispersion in optical fiber are studied and
numerically analyzed. Based on the analysis, the theoretical model of higher-order dispersion compensation with phased
modulator is presented, with emphasis on the third-order dispersion. According to the theoretical model, simulation
models based on VPItransmission is designed. Finally, experimental schemes are designed, and experiment is finished:
200-fs pulses propagate through a 47-km fiber link, including a 39.8-km SMF (single-mode fiber) and a 6.71-km DCF
(dispersion-compensation fiber). In that experiment, the oscillating tails are completely suppressed and the third-order
dispersion is successfully compensated with the phase modulator. Moreover, the parameters of modulator are optimized
with VPItransmission Modeling.
PMD compensation and mitigation with new modulation formats in WDM System
Show abstract
We study the polarization-mode dispersion (PMD) compensation and mitigation performance, using a single PMD
compensator to compensate several channels at the same time with degree of polarization (DOP) as the feedback signal
in a 2 40 / Gb s × WDM system. Particle-swarm optimization (PSO) algorithm is used to search and track the dynamic
degree of polarization (DOP) to achieve the adaptive PMD compensation. New modulation formats are used to mitigate
PMD, and the dynamic combination of PMD mitigation taking CSRZDPSK and CSRZDQPSK as the advanced
modulation formats have been successfully completed. The numerical results show that the differential phase-shift keyed
(DPSK) and differential quadrature phase shift keying (DQPSK) modulation formats are more suitable for PMD
mitigation system than the on-off keying (OOK) modulation format. Furthermore, DQPSK format can simultaneously
double WDM spectrum-packing efficiency and upgrade the system capacity while it can still has the same mitigation
performance as the DPSK format in the PMD compensation system. These features make them greatly attractive for
high-speed long-haul WDM system.
The influence of PMD on the degree of polarization ellipsoid
Show abstract
The effect of PMD on the three axes of the degree of the polarization (DOP) ellipsoid is discussed in the different
modulation format systems. The results show that the minimum axis of DOP ellipsoids is suitable for a feedback signal
in the compensation systems. In addition, the mitigation performances of DPSK formats are superior to that of OOK
format.
PMD compensation in true time delay system using Faraday Rotation Mirror
Show abstract
We firstly propose an approach to compensate the polarization mode dispersion (PMD) effectively in optical
true time delay (TTD) system composed of a Faraday Rotation Mirror (FRM), a normal 3-port circular. The
TTD system can preserve an arbitrary input state of polarization regardless of any external perturbations, and
is complete free from polarization effects. We demonstrate experimentally the polarization-stability of the TTD
system and discuss the RF correspond of the TTD system.
Tunable chromatic dispersion compensation using chirp control based on XPM in a SOA
Show abstract
We demonstrate a tunable chromatic dispersion (CD) compensation technique using a semiconductor optical amplifier
(SOA) and a coil of dispersion compensation fiber (DCF). Based on cross-phase modulation (XPM) in the SOA, the
transient chirp of the received signal can be adjusted by tuning the drive current of the SOA and the power of clock
pulse. In this way, a 10-Gbit/s tunable CD compensation setup, ranging from -40ps/nm to 60ps/nm, is realized without
changing the length of the DCF.
Electronic Processing
Pattern sensitivity in electronic dispersion compensation using full optical-field reconstruction
Show abstract
We investigate the pattern-dependent decoding failures that occur with electronic dispersion compensation (EDC) when
using full optical-field reconstruction, and find that the performance of such an EDC receiver may be degraded by an
isolated '1' bit surrounded by long strings of consecutive '0's. By reducing the probability of occurrence of this kind of
isolated '1', we experimentally achieved 10Gbit/s on-off keyed signal transmission over 372km field-installed singlemode
fiber without optical dispersion compensation.
Electronic signal processing in optical communications
Show abstract
Optical communications is undergoing a digital revolution, as digital signal processing (DSP) emerges as a practical
solution for robust long-haul transmission. In contrast to previous systems, in which optical dispersion compensation
was considered a necessity, recently uncompensated long-haul transmission has been demonstrated using DSP at the
transmitter, receiver, or a combination of the two. We review the historic developments of electronic signal processing
as applied to optical communications before focusing the latest developments, namely digital coherent systems. We then
discuss the salient features of the electronic signal processing schemes currently under investigation before discussing
the challenges and opportunities offered by electronic signal processing.
Simple eye closure penalty estimate for amplitude noise-degraded signals
Show abstract
We present a simplified model for a simple estimation of the eye-closure penalty for amplitude noise-degraded signals.
Using a typical 40-Gbit/s return-to-zero amplitude-shift-keying transmission, we demonstrate agreement between the
model predictions and the results obtained from the conventional numerical estimation method over several thousand
kilometers.
Network Elements II
Design of sparse mesh for optical network on chip
Show abstract
Nanoscale CMOS technologies are posing new network on chip concepts to IC designers. However, the electronic
network on chip design faces many problems like energy consumption, long delay and limited bandwidth. Hence, optical
network on chip appears as a good candidate to solve these problems. The advances in nanophotonic technology make it
more realistic. A new sparse mesh is proposed for optical network on chip. Two types of non-blocking optical node
architecture are also proposed to build up core node and switch node. The new architecture fully utilizes the property of
XY routing in 2D mesh network, thus saving the number of microring resonators used. The comparisons are made with
traditional mesh in number of microring resonators, loss and energy. The results show that the proposed sparse mesh
achieves the best in all the aspects. For example, it uses 68% less number of resonators than the traditional mesh. We
simulated 2D sparse mesh optical network on chip, and showed network performance under different traffic loads and
data sizes. The results show sparse mesh achieves lower average delay and higher throughput than the traditional mesh.
Micro-ring resonators fabricated by focused-ion-beam on SOI
Show abstract
We present the fabrication of high Q factor micro-ring resonators on SOI substrate by directly focused-ion-beam (FIB)
milling. Micro-ring resonators with diameters of 10 μm and 80 μm are fabricated and their corresponding intrinsic Q
factors are 4,000 and 130,000, respectively.
Slow light and its applications into all-optical networks
Show abstract
Slow light using Stimulated-Brillouin-Scattering (SBS) in optical fiber is now an enabling technology for all-optical
network functionalities. A brief review of recent advances in related research will be given, highlighted by optical
communication system demonstrations.
Experiment study on reducing SOA induced crosstalk by CW light injection and dispersion management
Show abstract
Semiconductor optical amplifiers(SOAs) application are not as widespread as one would expect. The reason lies in the
severe interchannel crosstalk experienced by the signals in a wavelength-division multiplexing(WDM) link using SOA.
Theoretical study on channel crosstalk due to gain saturation in SOAs is presented. A significantly higher penalty is paid
at more channels because of the gain saturation characteristic of SOAs. Crosstalk mitigation techniques in SOAs are
studied. We have demonstrated theoretically and experimentally that a CW light propagating with signal can mitigate
crosstalk in SOAs at channel rates of 40Gb/s. Reduction of crosstalk in SOA by amplifying dispersed WDM signals is
confirmed experimentally. Based on the results of the experiment, a novel dispersion management scheme is proposed to
prevent the interchannel crosstalk caused by cross-gain modulation.
The construction of a FBG-based hierarchical AOFSN with high reliability and scalability
Show abstract
To improve the reliability and scalability that are very important for large-scale all optical fiber sensor networks
(AOFSN), three-level hierarchical sensor network architectures are proposed. The first two levels consist of active
interrogation and RNs, respectively. The third level called sensor subnet (SSN) consists of passive FBGs and a few
switches. As AOFSN is mainly multiplexed by wired and passive FBGs, the routing algorithm for scanning sensors is
determined by the virtual topology of SSN due to the passivity. Therefore, the research concentrates on the construction
of SSN and aims at proposing regular and unicursal virtual topology to realize reliable and scalable routing schemes.
Two regular types of SSNs are proposed. Each type consists of several sensor cells (SC), square-based SC (SSC) or
pentagon-based SC (PSC) and is scaled several times from the SCs. The virtual topologies maintain the self-similar
square- or pentagon-like architecture so as to gain simple routing. Finally, the switch architecture of RN is proposed for
the reliability of the first two levels; and then, the reliability and scalability of SSN are discussed in view of how much
link failures can be tolerant, and how each SC is scaled to maintain the self-similarity, respectively.
Light Generators
Photonic monocycle pulse generation and modulation for ultra-wideband-over-fiber application
Show abstract
In order to integrate local ultra-wideband (UWB) environment into fixed wired networks or wireless wide-area
infrastructures and eliminate the high cost of microwave electrical circuits or devices, UWB-over-fiber systems have
emerged to exploit the advantages offered by optical fiber. We experimentally demonstrate a photonic UWB monocycle
pulse generation and pulse position modulation (PPM). The UWB monocycle pulse with inverse polarity can be
generated based on the two differently-biased Mach-Zehnder modulators, subsequently the PPM of the UWB monocycle
pulse is realized through the nonlinear polarization rotation (NPR) arising in a semiconductor optical amplifier (SOA).
We proposed and experimentally demonstrated an effective procedure to generate and maintain a linear output state of
polarization (SOP) during the course of the nonlinear polarization rotation (NPR) of an SOA. High performance of
polarization switching can be achieved. The proposed scheme is more preferable for the UWB-over-fiber applications
due to its compact size and high stability.
A novel optical pulse source based on optoelectronic oscillator
Show abstract
A time- and wavelength-interleaved (T- W-interleaved) optical pulse source based on optoelectronic oscillator is
presented. By utilizing spectral slicing, a multi-loop configuration is formed in OEO system, which can effectively
suppress side-modes. In addition, this configuration is able to generate multi-wavelength optical pluses which can be
arranged T- W-interleaved optical pulse stream at different nodes. In this system, 10-ps-wide optical pulses at 5GHz
repetition rate are generated with 1ps timing jitter (in the 100Hz-1MHz range) and -100dBc/Hz spurious modes
suppression, Along with the optical outputs, 5GHz electrical signal with low phase noise (-113dBc/Hz at 10kHz offset
from the carrier) is also obtained.
Photonic generation of ultra-wideband monocycle and doublet pulses using simplex semiconductor optical amplifier
Show abstract
We demonstrate two all-optical methods for UWB pulse generation based on various nonlinearities of the semiconductor
optical amplifier (SOA), namely, self phase modulation (SPM), and cross gain modulation (XGM). In the first method,
we present UWB doublet generation based on SPM. The monocycle pulse is generated from dark return-to-zero (RZ)
signal, and then converted to doublet pulse by injecting an additional probe signal with the SMF transmission. For the
first time to best of our knowledge, we report that the generated doublet pulses are transmitted over 5km SMF by proper
dispersion compensation without distortion. Second, we present UWB doublet generation by XGM of two cascaded
SOAs. The configuration of our all-optical methods is compact and simple.
Supercontinuum generation in photonic crystal fibers with different dispersion profiles
Show abstract
It has been investigated of nonlinear propagation of femosecond pulse and supercontinuum generation (SCG) in three
photonic crystal fibers (PCFs) with different dispersion profile in the 1550nm window by numerical stimulation. The
influence of higher-order effects on supercontinuum, including higher-order dispersion (HOD), self-steepening (SS), and
stimulated Raman scattering (SRS), are discussed in detail as well. The results of numerical simulations show that group
velocity dispersion and self-phase modulation take main effect in the initial stage. In the PCF with anomalous dispersion,
SRS plays main role when the propagation distance increases, which induces a red-shift of the central wavelength,
suggesting the appearance of soliton self-frequency shift. In the PCF with near-zero anomalous dispersion, HOD plays
main role. This results in the fission of higher-order solitons and remarkable broadening of the pulse spectrum. In the
PCF with normal dispersion, higher-order effects have almost no effect on the pulse. The Gaussian pulse wave broadens
to rectangular symmetrically, and the pulse spectrum broadens symmetrically, too. However, the broadening is smaller
than the former two cases.
Time- and wavelength-interleaved picosecond pulse source with tunable channels and repetition rate
Show abstract
A time- and wavelength-interleaved optical pulse source, which is based on spectral slicing and dispersion management,
is proposed and experimentally demonstrated. The pulse source has a simple configuration, and both the repetition rate
and the wavelength channels can be tuned easily.
WDM Transmission and Modulation Formats
WDM transmission systems based on SOAs and alternative modulation formats
E. Ciaramella,
G. Contestabile,
A. D'Errico,
et al.
Show abstract
Using POLSK (POLarization Shift Keying) and DPSK (Differential Phase Shift Keying) formats we fully
exploit Semiconductor Optical Amplifiers (SOAs) for signal amplification in practical WDM Nx10 Gbit/s systems.
Record transmission experiments are presented, thus making SOAs a competitive amplification alternative in
metro and extended-metro networks.
High spectral-efficiency DWDM transmission with mixed data rates and signal formats
Show abstract
Optical fiber transport networks have been evolving rapidly to meet the demands of today's telecommunications by
providing unprecedented transmission capacity and reach. In dense wavelength-division-multiplexing (DWDM)
transport systems, 10-Gb/s channels are widely deployed, and 40-Gb/s channels are starting to be added in the same
systems. In the foreseeable future, 100-Gb/s channels are expected to be carried. The realization of such high spectral-
efficiency DWDM systems with mixed data rates and signal formats presents several technical challenges. In this paper,
we review these challenges and discuss promising technologies that may potentially address these challenges.
Statistics of intrachannel four-wave mixing induced phase noise in coherent RZ-DQPSK transmission systems
Show abstract
Digital signal processing (DSP) based coherent detection attracts extensive studies recently. DSP technology simplifies
coherent detection and brings it more advantages and channel impairments can be compensated electrically. The lumped
dispersion compensation scheme makes the fiber link simple, flexible and potentially cost effective. However, such
pseudo-linear long haul transmission systems are greatly degraded by intra-channel nonlinearities at high bit rates. The
optical pulses are highly dispersed and overlap strongly during propagation, resulting serious intrachannel four-wave
mixing (IFWM). IFWM introduces pattern dependent nonlinear phase shifts to the signals. It has been pointed out that
IFWM induced phase noise are correlated from symbol to symbol. The autocorrelation function has been studied in
detail. Here we extend the result to fiber link with single mode fiber (SMF) for transmission only. We studied the
statistics of IFWM induced phase noise in Return to Zero-Differetnitally coded Quadrature Phase Shift Keying (RZDQPSK)
transmission systems with identical fiber spans and SMF fiber spans numerically. The results show that the
phase noise correlation of neighbouring bits is reduced for the latter one but the correlation length is increased with fiber
span number and chromatic dispersion value.
RoF and Wireless Networks II
Subcarrier demultiplexing using a tunable single resonance microwave photonic filter in radio-over-fiber system
Show abstract
A method for subcarrier demultiplexing in Radio-over-Fiber system has been proposed and verified experimentally. A
continuously tunable single resonance microwave photonic filter using the tunable fiber Mach-Zehnder interferometer
(MZI) as the slicing filter, is implemented to realize the demultiplexing. Two subcarriers, one is 2.4GHz representing the
wireless LAN signal , the other is 900MHz representing the Cellular signal, can be demultiplexed separately. The
proposed approach has been demonstrated both theoretically and experimentally.
Optical impairments mitigation in millimeter-wave fiber-wireless systems
Show abstract
Hybrid fiber-wireless networks for fixed wireless access operating in the millimeter-wave wave (mm-wave) frequency
region have been actively pursued to provide untethered connectivity to ultra-high bandwidth communications. The
architecture of such radio networks requires a large number of antenna base stations with high throughput to be deployed
to maximize the geographical coverage with main switching and routing functionalities located in a centralized location.
The transportation of mm-wave wireless signals within the hybrid network is subject to low opto-electronic conversion
efficiency, fiber chromatic dispersion and also signal degradation due to nonlinearity along the link. One of the major
technical challenges in implementing such networks lies in the mitigation of the various optical impairments that the
wireless signals experience within the hybrid network. In this paper, we present an overview of the different techniques
and schemes to overcome some of the signal impairments in transporting mm-wave radio signals over optical networks.
The transmission performance of the MPPM modulaton in indoor optical wireless communication based on white LED
Show abstract
White LED (light emitting diode) offer advantageous such as high brightness, lower power consuption and long life
spand, and is expected to be the next generation of lamp. The other merits of LED are high sensitivity and fine
modulation performance. An indoor optical wireless communication system is propsed and three kind of modulation
schemes are compared in band requirement and power requirement. Nine LED lights are installed in the different of the
room celling, so the RMS (root-mean-square delay spread) delay is also consided in hight bit rate enviroment, the
power loss and BER are presented under different time delay. The simulation results show that, the MPPM is bandwidth
efficeient than PPM and OOK. At the condition of high bit rate, MPPM performance much better than OOK and PPM
with low BER.
Optical Signal Processing II
High speed modulation format transformation from return-to-zero ASK to return-to-zero FSK based on nonlinear polarization rotation
Show abstract
Experimentally, investigation of nonlinear polarization evolution induced by cross phase modulation in
optical fiber and its impact on transmission link are circumstantiated in this letter. We experimentally demonstrate
that the use of 500-m length of highly non-linear fiber readily allows for our novel approach of implementing
high-speed format transformation from return-to-zero amplitude-shift keying (RZ-ASK) to return-to-zero
frequency-shifting keying (RZ-FSK) at 40Gb/s and above based on cross-phase-modulation-induced polarization
rotation. The high-performance feasibility is verified and the operating parameters are achieved.
All-optical NRZ to RZ format conversion using bistable semiconductor ring laser
Show abstract
In this paper, we propose and experimentally demonstrate an all-optical non-return-to-zero (NRZ) to return-to-zero (RZ)
format conversion using semiconductor ring laser (SRL). A 155Mb/s NRZ optical data signal is injected into the
counterclockwise (CCW) direction of the SRL and an optical logic clock signal is injected to the clockwise (CW)
propagation direction. The power and wavelength on both sides are adjusted so that during the 'high' level of the clock,
the SRL is held to the CW direction regardless of the logic value of the corresponding data bit. The SRL will only be
switched to the CCW direction when the input data is 'high' and when the clock level is 'low'. Therefore the NRZ
format signal is converted to RZ format signal, with a duty cycle decided by the duty cycle of the optical clock.
Extinction ratio of > 10 dB has been achieved and the scheme can also be used for all-optical 3R. Although the speed of
the signal is yet limited, higher speed can be achieved with faster SRL devices.
NRZ-DPSK to RZ-BPSK all-optical format conversion using optical filter and SOA-MZI
Show abstract
We propose and demonstrate all-optical format conversion from nonreturn-to-zero differential phase-shift-keying
(NRZ-DPSK) to return-to-zero binary PSK (RZ-BPSK) at different bit-rates, using a tunable band-pass filter, a
semiconductor optical amplifier (SOA) fiber ring laser and an SOA based Mach-Zehnder interferometer (SOA-MZI).
The filter acts as the DPSK demodulator and also as the differential decoder. It converts the NRZ-DPSK into the RZ
signals, which is equivalent to the data information before differential encoding. The SOA fiber ring laser is used to
recover the clock signals from the demodulated RZ signals at different bit-rates. In the subsequent SOA-MZI, the RZ
signal is used to modulate the recovered clock signal which is synchronous to the demodulated RZ signal. Thus, the
amplitude information is encoded onto the phase of the clock signal, through cross gain modulation (XGM) and cross
phase modulation (XPM) effects in the SOA-MZI. The converter can be operated at flexible bit-rates and used as the
interface between long-haul WDM and OTDM systems.
All-optical 40-Gb/s RZ-DPSK to phase-incorporated ASK-Manchester format conversion
Show abstract
Based on a Mach-Zehnder interferometer and optical temporal time delay (OTDL), we propose and demonstrate
experimentally an all-optical 40-Gb/s RZ-DPSK to ASK-Manchester format conversion. This obtained ASK-Manchester
signals have the phase changes due to the demodulation of RZ-DPSK, which is called as phase-incorporated
ASK-Manchester signal. Compared with pure Manchester signal, the simulated results show that the phase-incorporated
ASK-Manchester signal has a compact optical spectrum and lower power at the low radio frequency (RF) frequencies, which
presents high tolerance on chromatic dispersion and little the cross-talk between payload and label. Moreover, the efficiency
and the BER performance of conversion and the dynamic range of fiber input power, transmission length, and chromatic
dispersion tolerance of the converted ASK-Manchester are detailed discussed. Less than 1-dB power penalty over 50-km
SMF transmission is observed.
A photonic digital-to-analog conversion based on multi-wavelength sampling
Show abstract
A novel digital-to-analog converter based on multi-wavelength pulse source is proposed and primarily demonstrated by
experiment. The multi-wavelength pulse train which has been pretreated is separated in time domain through dispersion.
The pulse of different wavelength corresponds to the input digital data. Only one electro-optical modulator is needed in
the scheme. In the primary experiment, a 3-bit photonic digital-to-analog converter with a sample rate of 2.5 Gb/s is
realized. The scheme is simple and compact compared with the scheme using multiple electro-optical modulators.
A PMD supported high-speed optical frequency-domain IM-DD transmission system
Show abstract
A novel high speed Optical Frequency-domain Transmission method and System (OFTS) based on two time
lenses is proposed and analyzed in this paper. By using the unchanged spectral profile through light
propagations in fiber, the long-haul optical transmission over 100Gbps per channel can be achieved with
highly tolerance of linear distortion such as PMD, chromatic dispersion, time jitter etc. In the novel method
and system, a time lens is used at the transmitter to convert the initial time domain signal into frequency
domain signal. And at the receiver, another time lens is used to transform the received frequency domain
signal back to time domain. To prove the advantages of OFTS, a specifically designed 10×100Gbps OFTS is
numerically simulated over 1880km transmission without PMD compensation.
High-speed Transmission Systems
Modeling of ultra-high speed optical transmission systems
Show abstract
Key issues related to the modeling of ultra-high speed transmission are discussed in this paper. These topics include
components modeling, link modeling and BER estimation. Different solutions for the transport of 100 Gb/s over a single
wavelength including technologies such as coherent detection, polarization multiplexing, optical OFDM, and digital
signal processing are reviewed and compared with means of numerical simulations.
Advanced photoreceivers for 40 and 100 Gbit/s optical communication networks
A. Umbach
Show abstract
The rapidly increasing bandwidth demand requires deployment of 40 Gbit/s systems and 100 Gigabit Ethernet in the near
future. Different reach applications exploit advanced modulation formats employing spectral shaping and phase coding.
The resulting different solutions for photoreceivers are summarized and efforts within the industry towards integrated
solutions are described. First results of integrated DPSK receivers with co-packaged delay interferometers will be
presented.
High-speed FSK signal generation and transmission labeled with ASK
Show abstract
We propose a method to generate high-speed frequency-shifted keying (FSK) signal by demodulating two phase-shifted
keying (PSK) signals with proper wavelength detuning. The generated FSK is easy for detection and has a small crosstalk
to optical label signal. In an 85km SMF transmission demonstration, we achieve 1.5dB power penalty in 10Gbit/s
FSK payload and 1dB power penalty in 155Mbit/s amplitude-shifted keying (ASK) label. Compared with the phase
continuous FSK, this kind of FSK occupies wider bandwidth due to its phase discontinuity but is simpler in its
generation.
Optical Monitoring and Compensation II
Research on polarization-mode dispersion compensation performance of optical DQPSK modulation format
Show abstract
Polarization-mode dispersion compensation performance of optical DQPSK is studied in this paper. Firstly, the
simulation model for the back to back system of optical DQPSK is established by using Matlab. The optical power
spectra and eye diagram of different DQPSK modulation formats are obtained. Then, we adopt two pseudo random
binary sequences as input data streams. In the back to back DQPSK system, by means of precoding, modulation and
demodulation we obtain exactly the same as the original signal. The system for simulation is verified. At last, we add the
polarization-mode dispersion compensation program module to the back to back DQPSK system. The result is shown
that the modulation formats with smaller bandwidth have better PMD compensation performance. and that PMD
compensation performance of DQPSK is better than that of OOK and DPSK. CSRZDQPSK combines the
carrier-suppressed feature of CSRZ formats and specific spectrum characteristic of DQPSK formats, thereby it has the
best performance of PMD compensation performance.
Deficiency monitoring of DPSK signal using coherent hybrid
Show abstract
A method called coherent hybrid is proposed to monitor the deficiency of differential phase shifted keying (DPSK) either
generated by the bias offset drift of Mach-Zehnder modulator or an unmatched drive voltage applied to a phase
modulator (PM) is proposed and demonstrated. The hybrid power ratio of the maximum to the minimum after mixing the
unmodulated local oscillation lightwave with the modulated signal from the same light source is employed to measure
the degree of deficiency, simultaneously eliminate the dependence on light source power. Our experimental results
reveal that a±5% bias offset of MZI can produce 0.3dB power variation, larger than that of 0.02dB in the traditional
method by measuring the signal average power, and a drive voltage with a more than 10 percent deviation from the halfwave
voltage can be detected when it is applied to a PM. A feedback and control circuit based on this scheme is
developed and applied in our system. The impairments given by the unparallel orientation between the polarizations of
signal and local oscillation lightwave and the transient time of modulation signal pulse is discussed. By properly setting
the control parameters in the feedback control process, the impairments can be minimized.
All-optical performance monitoring of multi-bitrate and multi-format signals based on optical sampling for transparent optical networks
Show abstract
All-optical performance monitoring based on optical sampling was proposed for multi-bitrate and multi-format signals in
transparent optical networks. The performance of 42.7-Gb/s RZ-DQPSK and 10.7-Gb/s RZ-DPSK signals were
successfully monitored and correlated with the actually measured BER.
The optical sampling based on semiconductor optical amplifier for optical performance monitoring
Show abstract
Progress in optical network has stimulated interest in optical performance monitoring (OPM). Optical sampling
technique is believed to be a promising candidate to monitor the physical state of the network. The theoretical model of a
monitoring system based on optical sampling in semiconductor optical amplifier (SOA) and software synchronized
algorithm is constructed. Compared with the results obtained by Optsim, the monitoring system model is proved. For
10Gb/s NRZ (RZ) optical signals, the differences on Q values between the results obtained by SOA and the ideal
sampling processes are 0.195dB (0.247dB), 0.988dB (0.594dB), and 1.707dB (0.596dB) for pump energy equal to, ten
times of and fifty times of the optical data signal energy respectively. The sampling device can induce degradations of
the sampling results. It is mainly because of the gain saturation and the nonlinear effects in SOA. The high input power
can make the gain saturated deeply and further influence the probe and conjugate outputs. At the same time, the pump
power should not be too low. The proper pump power will obtain better sampling linearity and better sampling results.
Poster Session
All-optical ultra-wideband monocycle pulse generation using polarization state rotation filtering
Show abstract
We present a novel method to generate ultra-wideband (UWB) monocycle pulses using polarization state rotation filtering of optical negative pulses. Monocycle-like optical pulses with reversed polarities can be generated with appropriate polarization adjustment.
Supercontinuum spectrum generation in dispersion-flatted fibers with concave dispersion profile
Show abstract
The supercontinuum (SC) spectrum generation is proposed in dispersion-flatted fibers with concave dispersion profile (DFF-CCDP). The effects of pulse characteristics and the fiber parameters on the SC spectrum characteristics are numerically investigated in the DFF-CCDP by using the split-step Fourier method. The characteristics of the SC spectrum become worse when the parameters are much smaller or greater. The parameters should be set according to the practical applications.
Effects of chirp and noises on autocorrelation characteristics of hyperbolic secant pulse
Show abstract
Effects of chirp and noises on autocorrelation characteristics of the linear chirped hyperbolic secant pulse are
numerically investigated. It is found that the intensity autocorrelation curve and the pulse waveform are unchanged with
the increase of the chirp parameter |C|. The spectral width and time-band product of autocorrelation spectral curve
increase with the increase of |C|. The autocorrelation curves broaden near the center of the curves and heighten at the
edges with the increase of the random noise, temporal window and sampling number. A method of filtering the random
noise is given which is useful for us to use the SHG-FROG analyzer or the instruments based on autocorrelation
technology.
Chirp in wavelength conversion based on XGM of SOA
Show abstract
An enhanced theoretical model for wavelength conversion of SOA is presented. The chirp for the converted signal is analyzed and confirmed by numerical simulation.
Evaluation of satellite optical communications system performance by Gaussian approximation method
Show abstract
Considering that shot noise is Poisson distribution and the envelope of background optical noise is Rayleigh distribution, the Gaussian Approximation method is firstly used to evaluate the performance of Satellites Laser Communications precisely. The Moment Generating Function expression of considering shot noise, background optical noise and hot noise is firstly derived. The system performance of On Off Key modulation of traditional method is compared with GA method in direct detection system. Results indicate that the performance of Satellites Laser Communications by GA is different from traditional method.
ROADM based on the narrow-band optical switching technology
Show abstract
In this paper, we theoretically and experimentally introduce a new reconfigurable optical add/drop multiplexers
(ROADM) module which bases on the narrow-band optical switch (NBOS) technology and achieves the narrow-band
optical switching with a Fabry-Perot cavity. In comparison with the analysis of the current ROADM technologies, the
NBOS-based ROADM module is proven to be cost-effective, low insertion loss, narrow-band, and has a more mature
technology. It would grow to be a cost-effective ROADM solution than any of the others.
Modulator bias control based on dither signal in 40Gb/s RZ optical transmission system
Show abstract
The bias drift effect in the packaged LiNbO3 modulator is investigated. The Bessel expansion of the dithered clock
shows that the harmonic component equal to the dither frequency can be synchronously demodulated to get the bias drift
and avoid the random phase difference between the clock or data and the dither signal. By using the time division control
method one control system can track two modulator bias drift in 40Gb/s RZ optical transmission system because the
optimum bias point changes very slowly.
Primary experiments on 2-D and 1-D fiber-type optical phased array
Show abstract
A 2×2 and a 1×4 fiber-type optical phased array with PZT phase shifters have been implemented. Fibers are adopted as
transmission paths and emitting antennas in the optical phased array system. By using the feedback optimization we had
proposed before, the inaccuracy of fiber length is overcome. By adjusting the phase shift of each PZT phase shifter
repeatedly according to the algorithm we had proposed for optimization, 1-D and 2-D beam forming and beam steering
in a short period of time have been observed respectively. Moreover, a 1×6 fiber array is also tried. Although the
interference is not stable enough, much narrower beams are achieved.
An ultra-long haul PON trunk fiber protector based on SOA
Show abstract
This paper describes the design of a burst-mode ultra-long haul PON trunk fiber protector based on SOA. It's
transparent to protocols and thus compatible with various PON systems. With this technology, the robustness
and transmission distance of PON network can be greatly improved and extended. The fiber protector supports
a maximum transmission distance of 50km and a 1:128 branching ratio. It supports automatic protection
switching of trunk fiber whose longest protection switching time is less than 20ms. In addition, in the design of
the ultra-long haul PON system, by EPON as an example, the ranging of EPON system, RTT compensation
and other parameters also need to be amended. As a result, this article also makes research and description
on synchronization, ranging, time delay compensation, and other key parameters of the EPON system.
Influence of in-band group delay ripple of chirp FBG on 40-Gb/s transmission using RZ and CSRZ formats
Show abstract
The effect of non-ideal dispersion and reflection characteristics of chirped fiber Bragg gratings (CFBG)
on the 40-Gb/s and 10-Gb/s transmission is investigated. The effect of group delay ripple (GDR) on
eye-opening penalty (EOP) of carrier-suppressed return-to-zero (CSRZ) and return-to-zero (RZ)
formats is analyzed and compared. The system penalty for different amplitude and period ripples are
quantified.
Photonic analog-to-digital conversion using LiNbO3 asymmetric Mach-Zehnder Interferometer
Show abstract
Asymmetric lithium niobate Mach-Zehnder interferometer and its applications in photonic analog-to-digital conversion
will be discussed. Two schemes based on the asymmetric interferometer will be proposed and analyzed. The first scheme
is the phase shift photonic analog-to-digital conversion using asymmetric interferometer and synchronized multiwavelength
optical sampling pulses. Because of the dispersion effect of the lithium niobate crystal, when multiwavelength
optical pulses enter into the interferometer, at the output port, different wavelengths will have different phase
differences between two arms. As a result, after interference, the transmission characteristics of different wavelengths
will have a phase shift between each other, and this is just the key issue of phase shift photonic analog-to-digital
conversion. The other scheme we will propose in this paper is a spectral encoded photonic analog-to-digital conversion.
The spectral transmission characteristic of the asymmetric interferometer will shift with the voltage change of the analog
signal, and this shift has an ideal linear relation with the analog voltage change. The peak wavelength of the transmission
spectrum can be detected to realize quantization of the applied analog signal. Using both schemes presented in this paper,
high sampling rate and high resolution optical analog-to-digital conversion can be realized.
A novel technology combined with free space optics communication and laser ranging
Show abstract
A solution is proposed, which combined with FSO communication and laser ranging in order to effectively integrate two
payloads. It is a transformation of feedback pulsed laser ranging. Laser ranging hardware and FSO communication
hardware share a lot in common. Detailed description of working principle, error analysis and elementary experiment
result is also included. The further analysis indicates that the measurement precision can reach sub-millimeter by
counting more ranging period. Moreover, when temperature varies 30°C, the measure distance varies 2.25cm. In this
case, temperature control is necessary for sub-millimeter measurement.
Design and simulation of the AC-coupled burst-mode receiver with a large time constant
Show abstract
Due to the Multipoint-to-Point nature of the uplink, the upstream data transmission in a GPON system is burst-mode,
and both the guard time and preamble time are short. This burst-mode nature of the GPON uplink brings many
challenges for the design of the burst-mode receiver. This paper presents a newly designed AC-coupled burst-mode
optical receiver. The AC-coupled receiver uses a large time constant and a high-speed reset switch. The concept of
cumulative bit difference of pattern-dependent jitter is also put forwarded in this paper. Finally, simulation results are
provided to show the feasibility of the scheme.
All-optical format conversion and wavelength conversion based on four-wave mixing in HNL-PCF
Show abstract
Conversion from a 10 Gb/s non-return-to-zero (NRZ) signal at 1550 nm to a 10 Gb/s return-to-zero (RZ) signal at 1561
nm has been experimentally verified based on four-wave mixing (FWM) in a highly nonlinear photonic crystal fiber
(HNL-PCF) without the need of an extra NRZ-to-RZ conversion step.
The signal light at 1550nm was modulated by a NRZ electric pulse pattern. The pump light at 1555.540 nm generated by
a mode locked laser (MLL) was modulated by a clock signal. When these two lights were controlled strictly and
amplified to about 22dBm, the FWM effect happens in HNL-PCF. Two new spectrum peaks were achieved at 1545 nm
and 1561 nm respectively. Then the peak at 1561nm was filtered out and discussed.
Then we changed the wavelength of signal light from 1543nm to 1569nm. The FWM effect appeared in this whole
wavelength range. But the best quality of conversion signal was achieved at 1550nm. So when the signal at 1561nm was
filtered out , it was a pulse signal carrying information. The signals at other wavelength were pulse signals without
information.
Data-carried optical ultra-wideband monocycle pulses generation using two DGD modules
Show abstract
A novel method to generate ultra-wideband (UWB) signals based on two differential group delay modules and one
Mach-Zehnder Modulator is proposed. Both simulation and experiments verified that the method could generate two
kinds of UWB monocycles using low bit-rate non-return-to-zero data source (1Gbps). The monocycles have a fractional
bandwidth of 127% at centre frequency 5.5GHz.
Channel estimation based on adaptively modulated optical OFDM
Show abstract
To achieve adaptive modulation technology in Optical Orthogonal Frequency Division Multiplexing
(OOFDM) system, the channel estimation has to be made first and foremost. By imposing a symbol of
pilot signals after a certain amount symbols, the frequency response of a given transmission link can be
given out. The modulation format can be determined according to the frequency response. A high (low)
modulation format is used on a sub-carrier suffering a low (high) transmission loss. The modulation
format can be adjusted adaptively.
Controllable deflecting photorefractive spatial soliton
Show abstract
A numerical solution, travelling-wave-like spatial soliton is obtained by using
travelling-wave transform along with numerical methods to solve the photorefractive nonlinear
equation, and its necessary forming conditions are presented. The evolution properties of the
travelling-wave-like spatial soliton in the photorefractive crystal are investigated. The results
show that travelling-wave-like spatial soliton can not only keep its shape invariably, but also
translate its energy transversely. It is possible for controllable deflection of the spatial soliton. The
deflection angle depends on the magnitude of the transverse phase modulation coefficient. These
properties of the multi-soliton coherent interactions can be potentially applied in optical
computation.
The transmission characteristics for various dispersion management schemes for a novel 40Gb/s FSK transmitter
Yaoxiong Liang,
Bo Huang,
Xue Wang,
et al.
Show abstract
The transmission characteristics of a frequency shift-keying signal at 40Gb/s which generated by a novel scheme
are investigated under varying dispersion management. The resilience of fiber span, compensation ratio, and
power level are obtained.
All-optical UWB pulse generation and pulse shape modulation by using dual-in dual-out Mach-Zehnder Modulator
Show abstract
In this paper, a novel method to generate both monocycle and doublet UWB pulses is demonstrated, where pulse shape
modulation(PSM) can be easily implemented. Only two wavelengths and two modulators (one dual-in dual-out
modulator) are applied to achieve PSM. The data driving the first modulator is set to be 250Mbit/s 107-1 pseudo-random
bit sequence (PRBS). The 1GHz pulse pattern is synchronised with the data. The electrical spectrum of the signals
processes the centre frequency of 4GHz and -10dB bandwidth of 5.9GHz. The fractional bandwidth is about 147.5%,
which matches the FCC standard.
An all-optical AND gate based on asymmetric SOA-assisted Mach-Zehnder Interferometer
Show abstract
In this paper, a scheme for all-optical AND gate which exploits the cross-phase modulation (XPM) effect in an
asymmetric semiconductor-optical-amplifier-assisted Mach-Zehnder Interferometer (SOA-MZI) has been proposed for
the first time. No additional input beam such as a clock signal or continuous light is employed in the design, which is
required in other AND operations. The scheme is validated and the system performance under various parameters is
investigated through numerical simulations. This logic gate is helpful for future all-optical signal processing
configurations.
A novel receiving system based on optical taper applied to wireless optical communication
Show abstract
A novel optical receiver in wireless optical communication system is presented. The receiving method is demonstrated
based on an optical taper. The taper is mounted near the focus spot of the receiving lens along the principal axis. The
larger-area end of the taper receives the converging beam and the smaller-area end transmits optical power to detector or
optical fiber. In this way, the immunity to light beam deviation in wireless optical communication system can be
enhanced evidently. The theoretical and experimental results show that the system has a perfect performance and realizes
a low loss of 4dB for the range of field of view within 1mrad.
An optical quantizing and coding method for all-optical ADC based on asymmetrical nonlinear optical-loop mirrors
Show abstract
Self- and cross-phase modulation (SPM, XPM) in fiber is expected to play a major role in ultrafast all-optical analog-todigital
conversion(ADC), which can overcome the obstacles of inherently limited operating speed of electronic ADC. In
this paper, we propose an optical quantizing and coding method for all-optical ADC based on asymmetrical nonlinear
optical-loop mirrors . The multiperiod transfer function, which is the key to quantizing and coding, is achieved through a
careful design of the asymmetrical nonlinear optical-loop mirrors. We conducted proof-of-principle numerical simulation
and successfully demonstrated 3-bits all optical ADC with Gray code output, it is ready for experiments in future. The
proposed optical quantizing and coding, combined with existing optical sampling techniques, will enable ultrafast
photonic ADC without electronics.
Polarization control and stabilization using coordinate system transformation
Show abstract
A fast and accurate polarization control and stabilization system, which is based on coordinate system transformation, is
experimentally demonstrated. The typical control speed is 50-ms and the output SOP precision is 0.5°.
An all-optical frequency up-conversion solution implementing microwave photonic filter in a radio-over-fiber system
Show abstract
A novel all-optical frequency up-conversion method implementing microwave photonic filter in a radio-over-fiber (RoF)
link is proposed and demonstrated. The electrooptical phase modulator, electrooptic intensity modulator in combination
with 75-km single-mode fiber (SMF) is used to form the microwave photonic filter and fulfill the frequency upconversion
function at the same time. The technique requires large modulation index at the phase modulator, which
simultaneously increases the efficiency of the frequency conversion. The proposed approach has been demonstrated both
theoretically and experimentally.
Smart antenna system
Show abstract
Recent years the application of free-space laser communication system is become more important.A
smart antenna system combines multiple antenna elements with a signalprocessing capability to
optimize its radiation and/or reception pattern automatically in response to the signal environment. In
this paper, we mainly study the Optical adaptive Antenna Array in the free-space laser communication.
Numerical study on multimode optical fiber link considering higher-order VCSEL modes
Show abstract
Multimode VCSEL(Vertical Cavity Surface Emitting Laser) coupling into MMF (Multimode Optical Fiber) and its
influence on MMF link has been numerically studied. Considering the transverse misalignment between VCSEL and
MMF, coupling efficiency between VCSEL higher-order modes and modes of MMF is calculated and the Mode Power
Distribution in the MMF is obtained. Simulation of MMF link with multimode VCSEL indicates that the higher-order
VCSEL modes lead to decreasing of the eye opening of received signal. The transverse misalignment of VCSEL between
MMF greatly deteriorates the eye opening. With 300m OM3-MMF link , the EOP (eye-opening-penalty) is greater than
14dB when the misalignment between VCSEL and MMF is lager than 5μm.
The research and application of Ethernet over RPR technology
Show abstract
With service competitions of carriers aggravating and client's higher service experience requirement, it urges the
MAN technology develops forward. When the Core Layer and Distribution Layer technology are mature, all kinds
of reliability technologies of MAN access Layer are proposed. EoRPR is one of reliability technologies for MAN
access network service protection. This paper elaborates Ethernet over RPR technology's many advantages through
analyzing basic principle, address learning and key technologies of Ethernet over RPR. EpRPR has quicker
replacing speed, plug and play, stronger QoS ability, convenient service deployment, band fairly sharing, and so
on. At the same time the paper proposed solution of Ethernet over RPR in MAN, NGN network and enterprise
Private network. So, among many technologies of MAN access network, EoRPR technology has higher reliability
and manageable and highly effectiveness and lower costive of Ethernet. It is not only suitable for enterprise
interconnection, BTV and NGN access services and so on, but also can meet the requirement of carriers' reducing
CAPEX and OPEX's and increase the rate of investment.
Effect of stimulated- Raman-scattering on modulation instability in anomalous-dispersion regime of fiber
Show abstract
We focus the effect of stimulated-Raman-scattering (SRS) on modulation instability (MI)
in anomalous-dispersion regime of optical fiber from extended nonlinear Schrödinger equation. An
expression of the gain of MI is given and the ranges and the growth of the gain spectrum are
theoretically and numerically analyzed under considering SRS or neglecting SRS. The gain peak is also
theoretically demonstrated. The effect of SRS on the frequency spectrum of MI is few when incident
power is small. And incident power increases, the spectrum varies obviously, the range and the growth
of the gain is lower if considering SRS than that of the gain if neglecting SRS. We also find that the
maximum incident power will be limited by the fourth-order dispersion and will be enlarged by SRS to
an extent.
Performance of optical packet switch with partial inner wavelength method
Show abstract
In this paper, a partial inner wavelength method (PIWM) is proposed to enlarge buffering capacity of shared FDLbuffers.
An optical packet switch called OPS-PIWM is proposed to realize the PIWM. In addition, two optical packet
scheduling algorithms, i.e., greedy scheduling algorithm (GSA) and conservative scheduling algorithm (CSA) are
proposed to improve the performances of OPS-PIWM. The packet loss rate of OPS-PIWM versus the number of fiber
delay lines, the number of tunable wavelength converters, and the number of inner wavelengths are evaluated by
simulation experiments.
Statistical model for packet aggregation
Show abstract
A statistical model of the aggregation operation in an optical packet based network interface is presented. The operation
aggregates client-layer packets into optical slots, and includes a timeout parameter to limit the maximum delay.
Aggregation serves the purpose of providing an efficient filling of the large optical slots with smaller packets from the
client layer. The model will be utilized to derive an optimal choice of timeout parameter that will lead to an efficient
utilization of the optical packets.
Compensation performance of decision feedback equalizer in high speed optical communication system
Show abstract
This paper discusses electronics dispersion compensation (EDC) by decision feedback equalizer (DFE) in high speed
optical communication system using the LMS and the RLS algorithms, respectively. The theory of the decomposed DFE
derived from basic concept of DFE in EDC is studied. Compared with the traditional DFE, the system complexity of new
one has been reduced while it still keeps the high performance of DFE. Simulation results prove the validity of
practicability and indicate that the decomposed DFE using RLS algorithm can more effectively eliminate intersymbol
interference (ISI) after being transmitted long distance.
Numerical estimation of phase jitter in a dispersion managed link
Show abstract
The detailed origin of phase jitter in fiber-optic communication systems was firstly reviewed. An overview of
distribution of received phase jitter was presented. By contrasting the phase difference of sample pulses, variance of
phase noise of an DPSK system in dispersion-managed finite fiber spans was calculated and simulated by Matlab, and
the Gaussian shaped possibility density function (p.d.f.) was obtained. The performance of signal was analyzed by
estimating BER, which was calculated from the p.d.f.. By adding ASE noise of different power into the signal at each
EDFA, we found that the suppression of ASE noise contributing considerably to the improvement of signal performance.
Performance comparison of 2-D time-wavelength and coherent time-spreading OCDMA systems
Show abstract
We compared the theoretical bit-error-rate (BER) and throughput performance limits of 2-D time-wavelength
and coherent time-spreading optical code division multiple access (OCDMA) communication systems. The
results show that the BER performance of the coherent time spreading OCDMA scheme is much superior to 2-D
time wavelength scheme in the multiple access interference (MAI) noise limited case without considering beat
noise, and the beat noise affects the system performance seriously and appears as a dominant source of noise for
the two kinds of OCDMA systems. Nevertheless, the 2-D time wavelength scheme has better tolerance to beat
noise than coherent time spreading OCDMA scheme, and the superiority is more apparent with the increasing of
the code length N. While the coherent time spreading scheme has higher peak throughput, and it supports a
higher throughput than the 2-D time wavelength scheme at higher offered loads.
Analysis of the code parameters in asynchronous coherent time-spreading optical CDMA system
Show abstract
An analysis of the code parameters that are important to asynchronous coherent time-spreading OCDMA system is
presented. Relationship between the mean intensity of aperiodic cross-correlation and multiple-access interference
(MAI) and beat noise (BN) is deduced. Considering the mean system performance, MAI and BN can be calculated
directly from aperiodic auto-correlation function, and the aperiodic cross-correlation function is not needed. Hence, a
computational saving can be achieved For 511 length Gold sequence, coherent time-spreading OCDMA system can
support 12 interfering users for the mean performance.
All-optical phase modulation of a subcarrier in a radio over fiber system based on cross phase modulation
Show abstract
A new all-optical broadband phase modulator of subcarrier in radio over fiber (RoF) system has been
proposed. This modulator is based on cross phase modulation (XPM) in fiber. In this approach the
stability of the subcarrier modulation is improved significantly as most of the disturbance introduced
by environment variance can be cancelled when the lightwaves interfere in PD. A proof-of-concept
experiment demonstrates the feasibility of the modulator.
Optical-domain wideband microwave amplification system
Show abstract
An optical-domain wideband microwave amplification system which takes advantage of the
large bandwidth capacity of optical devices to amplify optically carried microwave signals is proposed. A
comprehensive theoretical model of the system including link gain, noise and spur-free dynamic range
(SFDR) is established, with which all kinds of performance of the system can be analyzed conveniently for
given system parameters. Based on the theoretical model, an experiment platform for the microwave
amplification system is established. The source microwave signal is modulated up to the optical domain by
carrier-suppressed modulation in a Mach-Zehnder intensity modulator (MZM) whose DC bias voltage is
controlled by an automatic-bias-voltage-control (ABVC) module. The output optical signal from the MZM
is amplified by a commercial erbium-doped-fiber-amplifier (EDFA) and then passes an optical band-pass
filter (OBPF) to filter out out-band amplified spontaneous emission (ASE) noise. Finally the optical signal
is fed into a photo-detector (PD) and the amplified microwave signal is obtained at the output of it. Owning
to the wide gain spectrum and the large small-signal gain of the EDFA, wideband microwave gain which is
larger than 17 dB is obtained over 12GHz-bandwidth. The microwave gain is quite stable while the input
microwave power varies from -60 dBm to -15 dBm and the input microwave frequency is tuned from 100
MHz to 12 GHz. The noise floor is approximately -137 dBm /Hz, which is mainly caused by the ASE noise
brought in by the EDFA. The SFDR of the system is third-order inter-modulation dominated and is
measured to be 113.1dB•Hz2/3.
A novel demultiplexing photodetector integrated with an arc absorbing cavity
Show abstract
A novel integrated demultiplexing photodetector which consists of a filter cavity and an arc absorbing
cavity is proposed in this paper. The top mirror of absorbing cavity is designed to be curved, which can
increase the times of light reflection. The maximum quantum efficiency of TE lightwave can reach
81.84%, while maximum of TM is 65.62%. An obvious near-to-zero domain of reflectivity of TM
lightwave leads to its low quantum efficiency. The impact of incident angle on quantum efficiency is
demonstrated by comparing two series of incident angles in two devices which have high and low
quantum efficiency respectively. In addition, the spectral response linewidth of this novel
photodetector is less than 0.8 nm.
Based on self-imaging phenomenon multiple coupled heterostructure photonic crystal waveguides power splitter
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A novel power splitter based on self-imaging phenomenon in multimode
heterostructure is designed and analyzed. Such a photonic crystal waveguide is a
structure combining square and hexagonal photonic crystal lattices. The size and
transmission of our designed new power splitter is much smaller and higher in
comparison with the conventional MMI power splitter. The device can be applied to
optical communication systems and be integrated easily with other optical devices.
The finite-difference time-domain (FDTD) method is adopted for the numerical
simulation of related structure. This approach can be extended to novel design of
MMI device based on photonic crystals.
Design and analysis of a multicast-capable optical cross-connect
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As multicast applications become more and more popular, implementing multicast in optical domain has attracted more
and more attention due to its more efficient bandwidth usage. The MC-OXC is the key for realizing multicasting at
optical layer and directly affects the performance of the multicast services in WDM networks. In this paper, a novel
mixed-integrated optical multicast switch for multicast-capable cross-connect is proposed. The new architecture uses
power splitters for multicast connections only, allowing unicast sessions to pass without enduring unnecessary power
loss. And also the performances of the MC-OXC are analyzed. We performed the cost and cost sensitivity analysis for
different MC-OXCs. The results show that the proposed architecture guarantees strictly nonblocking with lower costs.
Load balancing in OCDM optical packet switched networks
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Optical packet switching (OPS), which transfers the switching function from electrical domain to optical domain and
provides the smallest switching granularity, is the most potential candidate of switching form in the future optical
networks. Optical code division multiplexing (OCDM) is the mostly practical all-optical processing technology at the
state of the art. The experiments of optical packet switching with optical code (OC) label have demonstrated the
switching capability and advantages. But the timing of erasing and inserting label, which is similar with the bit-serial
label processing, is the stringent requirement of this scheme. OCDM optical packet switching, which encodes the
payload directly and removes the label when the payload is recovered at the decoder, has no stringent timing requirement.
Multiple access interference (MAI) is the main factor degrading the performance of OCDM optical packet-switched
networks. In this paper, the effects of MAI are studied at the end of optical label path where the packets experience
multiple hops. For eliminating the end-to-end BER, the optical label paths need to be established in an optimum way and
the load are required to be balanced. One load-balancing algorithm based on the end-to-end BER of OCDM path is
proposed to improve the network performance.
A pipeline scheme for real-time traffic in optical burst switching networks
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Optical burst switching (OBS) is regarded as a promising optical switching paradigm for next generation optical Internet.
More and more real-time traffic is transported by IP and it is important for OBS to support real-time traffic. Based on the
delay analysis of OBS networks, a pipeline scheme is proposed to reduce the delay and efficiently support real-time
traffic for OBS networks in the paper. When real-time traffic is transported in the core nodes of the established pipeline
and its burst head packet can not need to be processed. So the pipeline scheme reduces the offset time and delay of realtime
traffic. The simulation result shows that the pipeline scheme effectively reduces the end-to-end delay of real-time
traffic in the OBS networks.
Performance analysis of delay issue in unequal probability outputting based optical burst switching network
Show abstract
In this paper, the delay issue in unequal outputting probabilities applied optical burst
switching (OBS) network has been proposed and analyzed. The average waiting
length of queue in optical buffer and the average total length of queue in OBS core
router have been given. Analytical results indicate that, the performance of delay will
affected by the ratio among different length traffic.
An analysis on the load balancing strategies in wavelength-routed optical networks
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Routing and wavelength assignment (RWA) is one of the key issues in the wavelength-routed optical networks.
Although some RWA algorithms have been well performed to meet the need of certain networks requirement, they
usually neglect the performance of the whole networks, especially the load balancing of the whole networks. This is
quite likely to lead to some links bearing excessive ligthpaths and traffic load, while other links being at an idle state. In
this paper, the load distribution vector ( LDV ) is introduced to describe the links load of the networks firstly. Then by
means of minimizing the LDV of the networks, the load balancing of the whole networks is tried to improve. Based on
this, a heuristic load balancing (HLB) strategy is presented. Moreover, a novel RWA algorithm adopting the heuristic
load balancing strategy is developed, as well as two other RWA algorithms adopting other load balancing strategies. At
last, the simulations of the three RWA algorithms with different load balancing strategies are done for comparison on the
basis of both the regular topology and the irregular topology networks. The simulation results show that the key
performance parameters such as the average variance of links, the maximum link load and the number of established
lightpath are improved by means of our novel RWA algorithm with the heuristic load balancing strategy.
Constraint-based routing in path-protected translucent optical networks considering fiber nonlinearities and polarization mode dispersion
Show abstract
In this paper we present a novel physical layer impairment (PLI) aware routing and wavelength assignment (RWA)
approach combined with PLI-aware regenerator placement. We consider the dominant linear and nonlinear signal quality
degrading effects in 10 Gb/s non-return to zero (NRZ) on-off keying (OOK) systems by analytical models for amplified
spontaneous emission noise (ASE), filter crosstalk, group-velocity dispersion (GVD) and polarization mode dispersion
(PMD) as well as cross-phase modulation (XPM) and four wave mixing (FWM). As a topology for our study we have
chosen the COST266 reference network, which is a pan-European meshed network with a total of 28 nodes and 41
(bidirectional) edges. For this network demands have been defined based on a population-based model. To facilitate
transmission over very long path lengths regenerator pools have been placed sparsely at certain nodes due to cost
considerations. The regenerator sites are selected based on a heuristic algorithm taking into account the physical effects
resulting in signal quality degradation. Due to the high cost of optical-electrical-optical (OEO) conversion as few
regenerators as possible are deployed. In our investigations we assumed a 1+1 path protection scheme in the optical
layer. The exact assessment of the signal quality based on the current traffic situation using our methods permits a
network performance (wavelength blocking probability) comparable to an opaque network with only a small number of
regenerators.
A novel segment-shared protection algorithm in multi-domain optical mesh networks
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In this paper, we propose a novel segment-shared protection algorithm (SSPA) for multi-domain optical mesh
networks. In SSPA, intra-domain links and inter-domain links are protected with segment-backup paths respectively.
The segment-working path is protected with path shared protection in single-domain and the inter-domain link is
protected with shared segment-backup path that it could traverse several domains. The major advantage of SSPA is
its shorter recovery time than previous path protection in multi-domain optical mesh networks. The SSPA resolves
the inter-domain link protection problem successfully. The computer simulation results show that resources
utilization ratio of our proposed SSPA is near to the optimization algorithm that requires the global knowledge of
network topology.