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- Front Matter: Volume 7630
- Best Student Paper Competition
- Optical Fiber
- Optical Pulses
- Polarization Effects and Measurements
- Photonic Crystals
- Fiber Lasers
- Optical Processing
- Fiber Gratings
- Optical Couplers
- Photonic Crystal Fibers I
- Optical Waveguide Devices I
- Fiber Design and Fabrication
- Optical Waveguide Devices II
- Photonic Crystal Fibers II
- Optical Amplifiers
- Optical Devices 1
- Optical Fiber
- Optical Devices II
- Poster Session
Front Matter: Volume 7630
Front Matter: Volume 7630
Show abstract
This PDF file contains the front matter associated with SPIE
Proceedings Volume 7630, including the Title Page, Copyright
information, Table of Contents, and the Conference Committee listing.
Best Student Paper Competition
Optical time-slot swapping based on parametric wavelength exchange
Show abstract
We have experimentally demonstrated simultaneous 10-Gb/s optical time-slot swapping between return-to-zero (RZ)
signal format and non-return-to-zero (NRZ) signal format based on the parametric wavelength exchange (PWE) in the
highly-nonlinear dispersion shifted fiber (HNL-DSF). Original RZ and NRZ signals located at two different wavelengths
are exchanged after the PWE process. After exchanging between RZ and NRZ signals, the swapping ability involving
two different signal formats within particular time slot has been proved. Clear open eye diagrams of periodic mixed RZ
and NRZ signals are recorded on both wavelengths.
Phase-tunable polarization division multiplexing DPSK receiver using a single demodulator
Show abstract
We report a new design of differential phase-shift keying (DPSK) receivers which utilize a single demodulator to receive
polarization division multiplexed signals. More than 20 dB extinction-ratio can be achieved by optimizing the phase
detuning with a polarization controller in the receiver. Experimental demonstrations using 20 Gb/s polarization
multiplexed DPSK signals and 215-1 pseudorandom binary sequence are conducted to show the performance of the
proposed receiver. After 60 km of optical fiber transmission, the receiver has less than 3 dB power penalty at bit-error
rate (BER) of 10-9.
Refractive index sensor with acoustic grating in a low index contrast photonic bandgap fiber
Show abstract
We demonstrate and optimize a microfluidic refractive index sensor with ultra-high sensitivity based on an acoustic
grating in a solid core photonic bandgap fiber. The sensitivity of the acoustic grating's resonance is 17 900 nm/RIU
which corresponds to smallest detectable changes in refractive index of 8.4×10-6.
Simple technique for measuring Raman gain efficiency spectrum distribution in a single-mode fiber
Show abstract
Simple technique is proposed for measuring distributed Raman gain efficiency spectrum in a single-mode fiber based on
the bidirectional OTDR. The Raman gain efficiency spectra are successfully estimated easily from the relative-index
difference and wavelength dependence of the mode field radius (MFR).
Long distance fiber Bragg grating sensor system based on erbium-doped fiber and Raman amplification
Show abstract
A novel simple long distance FBG sensor system is proposed and demonstrated. It can easily achieve 45dB signal-tonoise
ratio (SNR) after transmitting along a 50km single mode fiber (SMF) by using only one 1W Raman pump laser
source at 1395nm and a segment of 5m Erbium doped fiber (EDF) inserted before the FBG.
Logic unit for CSRZ-OOK signals with the capability of simultaneously realizing logic OR and AND gates
Show abstract
To cope with the development of Carrier-suppressed-return-to-zero-on-off-keying (CSRZ-OOK) modulation format, it is
of great significance to investigate all-optical logic gates to process CSRZ-OOK format signals. To the best of our
knowledge, for CSRZ-OOK signals, only logic AND gate has been demonstrated while other logic functions haven't
been explored until now. In this paper, an all-optical logic unit to process CSRZ-OOK signals based on four-wave
mixing (FWM) arising in a semiconductor optical amplifier (SOA) is proposed. A logic OR gate and two logic AND
gates with the CSRZ-OOK format unchanged could be simultaneously achieved without reconfiguration in this single
unit. The performance of 40 Gb/s logic operation is firstly evaluated with numerical simulations by a comprehensive
dynamic model considering three-input induced FWM in an SOA. Then, experimental demonstrations at 10 Gb/s with
clear waveforms and high extinction ratios (ERs) further verify the logic integrity of this scheme.
Optical Fiber
Brillouin dynamic grating in optical fibers and its applications
Show abstract
A novel kind of all-optical dynamic grating with the reflectance and the center wavelength controlled by another optical
wave can be realized based on Brillouin scattering in polarization-maintaining optical fibers. This grating, called
Brillouin dynamic grating (BDG), has proved to be useful based on its unique characteristics in several applications such
as high performance distributed sensors and optically-tunable delay lines.
Investigation on temperature sensitivity of D-shaped fibers by manufacturing specified surface structure
Show abstract
Temperature sensitivities of D-shaped fibers with specified surface structures such
as thin film and periodic grating are investigated. The photo resister overlay can induce the
evanescent field coupling of the core mode to the cladding mode in the overlay. The mode
coupling can be modified by the overlay structures such as a single layer and periodic grating.
The temperature sensitivity of D-shaped fibers with versatile overlay structures is also
changed.
High temperature sensing characteristics of erbium-doped fiber using fluorescence intensity ratio technology
Show abstract
The fluorescence intensity ratio (FIR) technique for optical fiber-based temperature sensing is discussed in many
previous papers. But in the high temperature sensing the FIR technique has been researched a little. In this paper, the
temperature dependence of fluorescence in erbium-doped fiber between ~700 and ~1300 °C; is discussed and
experimentally demonstrated. 1450nm and 1530nm wavelengths are chosen to calculate the FIR, and the temperature
coefficient could achieve ~ 0.003dB/°C.
Optical Pulses
A novel scheme for tunable optical pulse generation based on fiber sagnac loop
Show abstract
A novel scheme for tunable optical pulse generation based on fiber sagnac loop was proposed and studied. The key
parameters of the optical pulse were analyzed and testified by simulations and experiments. The repetition rate of optical
pulse is twice the frequency of external square wave modulation signal and can be tuned directly by varying modulation
frequency. The maximal peak value can be achieved when the peak-peak value of the square wave modulation signal
was equal to the half-wave voltage of the phase modulator. Experimental results agree well with theoretical predictions
and simulations.
A 100 GHz pulse train generation by spectral filtering of a 10 GHz mode-locked fiber laser Output
Show abstract
We demonstrate a simple method to generate a high speed pulse train from a low speed pulse source by spectral filtering using a high finesse fiber Fabry-Pérot interferometer. Reasonably stable 100 GHz pulses at 1550 nm were obtained from a 10 GHz mode-locked fiber laser.
Propagation of high-power parabolic pulses in cubicon fiber amplifiers
Show abstract
We have theoretically studied pulse propagation in a normal-dispersion optical cubicon fiber amplifier (NDOCFA) with
an arbitrary longitudinal gain proflie, and have obtained an analytic solution for the nonlinear Schrödinger equation that
describles such an amplifier. The results show that the characteristics of self-similarity and linear chirp will be lost due to
third-order dispersion. However, by using a dispersion compensation technique, one can obtain efficient and high-quality
compressed pulses. The numerical simulation is consistent with the analytic results.
Polarization Effects and Measurements
Experimental demonstration of a wavelength tunable polarization OTDR using an SOA for received signal amplification
Show abstract
A wavelength tunable polarization OTDR utilizing a semiconductor optical amplifier for the received signal
amplification is proposed in order to realize stable operation. Measurement experiments are carried out for a fiber link
with a length of 5.7km and the state of polarization change along the fiber link is successfully estimated.
Design of broadband single-polarization single-mode holey fiber
Show abstract
We propose a novel structure of single-polarization single-mode(SPSM) holey fiber designed based on resonant coupling
effect. The proposed fiber is able to achieve SPSM operation over an ultra-broad bandwidth as large as 920nm ranging
from 1.48μm to 2.4μm, within which only one polarization state of the fundamental mode can be effectively guided.
With the aid of six smaller holes around the central core, the effective mode area of the fiber is enlarged and the
chromatic dispersion curve is flattened. The numerical results indicate that the proposed fiber achieves nearly zero
ultra-flattened dispersion over a wide spectral range and the effective mode area is approaching ~78μm2 at 1550nm.
Moreover, the structure shows superiority in output beam quality owing to the symmetry of the central core region, and
also exhibits great modal compatibility with SMF.
An experiment of polarization measurement using DSP-based control system
Show abstract
A Polarization measurement using DSP-based control system has been demonstrated in the experiment. The normalized
Stokes parameters and the degree of polarization which are varying at the speed of in the order of millisecond are measured
in real-time manner.
Photonic Crystals
The designs of 4×2 encoder based on photonic crystals
Show abstract
All-optical logic gate is a basic and crucial element for optical signal processing. In this paper, we propose a 4×2 encoder
based on two dimensional triangular lattice photonic crystals composed of cylindrical silicon rods. The main structure of
the device is a combination of both line defect Y branch and coupler photonic crystal waveguides. The computational
simulation is carried out by using a finite-difference time-domain (FDTD) method. The simulation results show that the
proposed all-optical photonic crystal waveguide structure could really function as a 4×2 encoder logic gate. In addition,
the distance between coupler photonic crystal waveguides, the length of coupler waveguides and the distance between
line defect Y branch waveguide structure are optimized for achieving the optimal performance for the proposed encoder
logic gates. This device is potentially applicable for photonic integrated circuits.
Folded Mach-Zehnder interferometer based on photonic crystal self-collimation effect
Show abstract
A Folded Mach-Zehnder interferometer (FMZI) in a two-dimensional photonic crystal is proposed. The FMZI consists
of one splitter and several mirrors. Light propagates between them employing self-collimation effect. Its two interfering
branches have different path lengths. The two complementary transmission spectra at two FMZI output ports are both in
the shape of sinusoidal curves and have a uniform peak spacing in the frequency range from 0.255c/a to 0.270c/a. The
peak spacing becomes smaller when the length difference between the two branches is increased. As self-collimation
light beams can cross each other without coupling, this FMZI is much smaller than non-folded interference-type filters in
photonic crystals. This FMZI may work as a wavelength division demultiplexer in high-density photonic integrated
circuits.
Terahertz waveguides based on photonic crystal
Show abstract
We propose and experimentally demonstrate a novel compact and integrated terahertz waveguide, which consists of
silicon photonic crystals with triangular lattice and a line defect waveguide in photonic crystal (PC) slabs. We also
directly measured the propagation loss of the line defect waveguides and obtained a value of 0.99dB/mm. The observed
waveguiding characteristics agree very well with three-dimensional finite difference time-domain calculations.
Asymmetrical interleaver filters based on one-dimensional photonic crystal theory
Show abstract
Based on the theory of one-dimensional photonic crystal, an asymmetrical interleaver filter is proposed. It is composed
of cascaded thin-film glass cavities. Each thin-film glass cavity is formed by evaporating several layers of reflecting
films on two surfaces of glass medium. Compared with other proposed structures, the proposed interleaver structure is
not only very simple but also easy to accomplish. Moreover, flat passband and stopband can be obtained by the
interleaver. A design example of a 50 GHz interleaver filter with duty cycle of 1:5 is presented. The influence of each
structural parameter on spectral performance, especially for the duty cycles is discussed. On this basis, design results of
interleaver filters with duty cycle of 1:3 and 1:4 are shown and analyzed. A design example of an interleaver filter with
five cascaded cavities is given at last.
Fiber Lasers
32Tb/s DWDM Transmission System
Show abstract
We successfully generated 114-Gb/s PDM-8QAM optical signal by novel scheme. Intradyne coherent detection of
PDM-8QAM optical signal with robust blind polarization de-multiplexing has been demonstrated by using a new cascaded
multi-modulus equalization algorithm. With RZ-shaped PDM-8QAM modulation and the proposed blind polarization
de-multiplexing algorithm, we demonstrate a record 33.9-Tb/s fiber capacity (320×114Gb/s) being transmitted over 580km
of ultra-low-loss SMF-28 fiber utilizing C+L-band EDFA-only optical amplification and single-ended coherent detection
technique, at a spectral efficiency of 4.2bit/s/Hz. Utilizing only C-band EDFA, we also demonstrate that 16.9-Tb/s capacity
(160×114Gb/s)) can be transmitted over 640km of standard SMF-28 fiber.
Influence of pump power on the output characteristics of multiwavelength erbium-doped fiber laser employing symmetrical nonlinear optical loop mirror
Show abstract
The influence of pump power on the output characteristics of multiwavelength erbium-doped fiber laser, which employs
the effect of the intensity-dependent loss induced by a power-symmetric nonlinear optical loop mirror, is investigated.
The results of studies show that the multiwavelength output characteristics including the number, the flatness and the
spectral region of output wavelength can be controlled by adjusting the pump power. To optimis the multiwavelength
operation, a suitable pump power must be chosen for this kind of laser.
Passive harmonically mode-locked erbium-doped fiber laser
Show abstract
Passive harmonically mode-locked erbium-doped fiber ring laser with scalable
repetition rates up to 1.2 gigahertz is experimentally demonstrated, to our best
knowledge, which is hitherto maximum repetition rate from only-erbium-doped fiber
laser. Owing to the acousto-optic effect, stable passive harmonically mode-locking
can only occur at some certain discrete repetition rates corresponding to resonant
frequencies of transversal acoustic wave induced by propagating optical pulses in
fibers.
Q-switched Yb-doped microstructure fiber laser using GaAs as saturable absorber
Show abstract
A passive Q-switched Yb-doped microstructure fiber (MF) laser is demonstrated using a GaAs wafer as the saturable
absorber. A high Ytterbium-doped fiber with a core diameter of 21 μm and a numerical aperture of 0.04 was used as the
active fiber. The large-diameter core allows for greater energy storage than conventional single-mode core designs and
the small NA of the core ensures the good beam quality of the laser. A pulse duration as short as 80 ns was obtained with
the maximum repetition rate of 830 Hz. The maximum average output power is 5.8 W at 1080 nm wavelength.
Characterization of fused-silica optical fibers delivery high-peak power YAG laser beam
Show abstract
The optical fiber delivery laser power technology in laser flexible manufacturing system is introduced.
The characteristics of optical fiber delivery Nd:YAG pulsed laser power through multimode silica fiber
are experimentally researched, which include beam spatial characteristics of fiber exit beam and the
capacity of optical fiber delivery high power laser. The effects of laser injection condition and optical
fiber bending radius on optical fiber delivery laser beam system are analyzed. The morphology
characterization of laser induced damage to optical fiber end-faces were measured and investigated.
The model of laser induced damage to fiber end faces is presented.
Optical Processing
Spectral phase OCDMA encoder/decoder using travelling interference fringe photo-writing technique
I. Fsaifes,
A. Millaud,
S. Cordette,
et al.
Show abstract
In this paper, we describe and investigate a new UV photo-writing setup using Travelling Interference Fringe (TIF)
technique for Fiber Bragg Grating (FBG) realization. A continuously moving fringe pattern is generated using two
electro-optical UV modulators and is synchronized with the fiber moving speed. FBG parameters such as chirp, phase
shift and apodization profile can be controlled with high precision. This method is used to realize repeatable, flexible and
complex profile spectral phase OCDMA encoders/decoders. Experimental realization results in good agreement with
numerical simulations are presented and discussed. The obtained encoders/decoders are tested within a system setup
using a supercontinuum optical source.
Receiver sensitivity improvement for NRZ-OOK signal by optical parametric amplifier-assisted detection
Show abstract
By using a fiber optical parametric amplifier, we demonstrate a novel pre-amplification scheme to improve receiver
sensitivity for 10-Gb/s non-return-to-zero on-off keying (NRZ-OOK) format with dual-end superposition of signal and
idler in the optical parametric amplifier (OPA). We achieve receiver sensitivity of -40.5 dBm at BER = 10-9. Compared
to its single-end counterpart, the receiver sensitivity can be improved by 2 dB.
Fiber Gratings
Polarization sensitivities of demodulation techniques for tilted fiber Bragg grating refractometer
Show abstract
The polarization sensitivities of demodulation techniques for tilted fiber Bragg Grating (TFBG) refractometer are
investigated theoretically with the complex mode based coupled mode theory. The use of perfectly matched layer (PML)
technique simplifies the radiation mode model. The numerical results show that both the normalized area detecting
technique and the power-referenced demodulation technique are highly polarization sensitive, the polarization sensitivity
increases with the grating tilted angle, thus, precise polarization control is essential in both of the demodulation
techniques.
The experimental fabrication of add/drop filters using a Bragg grating-assisted mismatched coupler
Show abstract
The unified coupled-mode formalism derived from Maxwell's equation is employed to analyze the add/drop filters using
a Bragg grating assisted mismatched coupler. An add/drop filter using a Bragg grating-assisted mismatched coupler is
fabricated and tested. The maximum reflectivity, 3dB bandwidth, insert loss at the drop port and reflective loss at the
input port of the filter are measured to be about 12 dB, 0.2 nm, 3.91 dB and - 7.39 dB, respectively.
Optical Couplers
Bragg grating-assisted optical triplexer using two silicon nanowire-based directional couplers
Show abstract
A triplexer based on silicon nanophotonic wire structure consisting of two Bragg grating-assisted directional couplers is
proposed, which can multi/demultiplex three different wavelengths through a compact device. The device has low loss,
low crosstalk, and a footprint of only 210 ×40 μm. The 1-dB bandwidth for the three channels located at 1310, 1490 and
1550 nm are 110, 20, and 20 nm, respectively.
Index profile engineering of multimode interference couplers
Show abstract
We propose a technique to improve the performance of high index contrast Multimode Interference (MMI) couplers. It is
shown that imaging errors can be almost completely removed if the refractive index profile of the multimode region is
properly designed. The proposed technique has been applied to design a 2x4 MMI 90º hybrid on SOI submicrometer
strip waveguides (silicon-wires). Results show that the optimized device exhibits an almost ideal performance.
Modified Hamming function weighted waveguide structure for the broadband and minimized mismatched optical couplers
Show abstract
We numerically investigate a new function modified from Hamming function to apply in weighting the waveguide
structure of a mismatched optical coupler with the characteristics of low crosstalk, short length, and broad C+L-band.
The full factorial design and beam propagation method are being used to seek the optimal structure parameters of
coupling waveguide. This modified Hamming weighting function (M-HWF) is proved to have the superior performances
to Hamming weighting function (HWF) in several ways. In theoretical computation, the M-HWF and HWF waveguides
have the coupling lengths of 11 mm and 16 mm, respectively at crosstalk of -40 dB and operating wavelength of 1.57
μm. After the numerical design of waveguide structure parameters, the M-HWF also obtain a shorter coupling length of
4.50 mm than coupling length of 5.90 mm of HWF at crosstalk of -40 dB and within the C+L-band (1.53~1.61 μm). The
M-HWF waveguide with the shortest coupling length of 4.5 mm can even reach a broader bandwidth between 1.50 and
1.70 μm.
Low-crosstalk, short-length mismatched optical coupler designed by new weighting function
Show abstract
A newly self-developed Broadband weighting function is presented to show the excellent results comparing with the Blackman and Hamming weighting function in applying to the waveguide structure of mismatched optical couplers for the demand of short-length, C+L-band, and low crosstalk. It is found that the coupler with the Broadband weighting function can reach the bandwidths between 1.360 to 1.700 μm with a coupling length of 2.5 mm and crosstalk of -35 dB. Obviously, the Broadband WF is suited in weighting the waveguide structure of a mismatched optical coupler to obtain a short coupling length, low crosstalk, and broad bandwidth.
Silicon wires and compact multi-mode interference splitters with an uneven splitting ratio
Show abstract
We report the fabrication and accurate measurement of propagation and bending losses in silicon wires with submicron
dimensions fabricated on silicon-on-insulator wafer. Propagation loss of 0.71±0.03dB/mm for the TE polarization was
measured at the 1.55μm. Loss of per 90º bend is measured to be 0.01dB for a bending radius of 5μm. Three types of
compact MMI splitters with different splitting-ratios were fabricated and measured. The splitting-ratios are respectively
50:50, 15:85 and 28:72. They exhibited low excess losses of about 1.5~3.9dB. The splitting-ratios were consistent with
the design values.
Analysis and fabrication of broadband add/drop filters using a Bragg grating-assisted mismatched coupler
Show abstract
The unified coupled-mode formalism derived from Maxwell's equation is employed to analyze the add/drop filters using
a Bragg grating assisted mismatched coupler. By writing a linearly chirped Bragg grating over the uniform coupling
region of the coupler, a filter with maximum reflectivity and 3dB bandwidth at the drop port about 20 dB and 0.8 nm,
respectively, is obtained. The experimentally measured results are in good agreement with the numerical calculations. A
broadband add/drop filter using a Bragg grating-assisted mismatched coupler can be obtained by writing a linearly
chirped Bragg grating over the uniform coupling region of the coupler.
Photonic Crystal Fibers I
Ultra-wideband single-polarization single-mode photonic crystal fiber with high nonlinearity and low dispersion
Show abstract
We report a novel design of photonic crystal fiber (PCF) with a rectangular array of four closely-spaced, highly elliptical
air holes in the core region and a circular-air-hole cladding. The proposed PCF is able to support ultra-wideband singlepolarization
single-mode (SPSM) transmission from the visible band to the near infrared band. With the aid of the inner
cladding formed by the central air holes, one polarization of the fundamental mode can be cut off at very short
wavelengths and ultra-wideband SPSM propagation can be achieved. The inner cladding also suppresses the higher order
modes and allows large air filling fraction in the outer cladding while the proposed fiber remains SPSM, which
significantly reduces the mode effective area and the confinement loss. Our simulation results indicate that the proposed
PCF has a 1540 nm SMSP range with < 0.25 dB/km confinement loss and an effective area of 2.2 m2. Moreover, the
group velocity dispersion (GVD) of the proposed PCF can also be tuned to be flat and near zero at the near infrared band
(~800 nm) by optimizing the outer cladding structure, potentially enabling many nonlinear applications.
A novel proposal for DWDM demultiplexer design using resonance cavity in photonic crystal structure
Show abstract
We propose an ultra compact structure for Dense Wavelength Division Multiplexing (DWDM) systems using resonance
cavity in Photonic Crystal (PC) structure. To the best of our knowledge, this is for the first time that a PC-based
demultiplexer has been achieved with 0.8nm channel spacing, -18.77dB and 4170 average crosstalk and quality factor,
respectively without using particular materials or complexities in fabrication. Two-dimensional (2D) Finite-Difference-
Time-Domain (FDTD) method is chosen for simulation in this work.
Optical Waveguide Devices I
Signal processing in silicon waveguides
Show abstract
We experimentally demonstrate all-optical signal processing functions using silicon microring resonators with a
450×250-nm cross section. These results include slow-light delay of phase-modulated data and microwave
photonic signal, wavelength conversion/multicasting, format conversions, optical differentiation, and concentric
micro-ring resonators with deeper notches for label-free bio-sensing applications.
Design of suspended SU-8 optical waveguides for ultrasmall bending
Show abstract
Small suspended SU-8 optical waveguides with a high refractive index contrast are designed and optimized. The singlemode
condition and the bending characteristics of the present waveguide are numerically calculated by using a fullvectorial
finite-difference method. Pure bending losses and transition losses of bending waveguides with different
bending radii and different core widths are studied. The simulation results show that a wider core is helpful to reduce the
pure bending loss. For example, when the core width is chosen as 2 m, a very small bending radius (~5 m) can be
achieved. However the transition loss is high. When a small total bending loss (<0.1dB/90º bend) is required, the
minimal bending radius is about 7 m when an optimal offset is introduced. A crossing structure with two arms to
support the suspended waveguides is designed and optimized by using a two-dimensional finite-difference time-domain
method. The structure parameters (e.g., the expanding width, the taper length and the length of the insert straight section)
of the crossing structure are optimized to minimize the excess loss. The optimal crossing structures exhibits a low excess
loss (<0.1 dB) and performs well in a wide wavelength range (1500 nm~1600 nm).
Polarization-insensitive electro-optical modulator based on polymer-filled silicon cross-slot waveguide
Show abstract
A silicon cross-slot waveguide filled with electro-optic polymer is proposed to release the polarization-dependent issue
of the electro-optic modulator. There are two slots in both the horizontal direction and vertical direction, so this
waveguide structure can confine both the TE and TM modes. The four silicon regions can be lightly doped as the
electrodes. There is slanted electric field in the slot region when the voltages are applied on the electrodes. The electric
field component act at principal optical axis whose electric-optic (EO) coefficient is r33 or r13 can be adjusted by
changing the voltages on the four electrodes. With optimal voltages, the effective refractive index of the TE and TM
modes can be changed equally. The Mach-Zehnder modulator based on cross-slot waveguide can achieve polarizationinsensitive.
Analysis and design of box-like filters based on 3×2 microring resonator arrays
Show abstract
This paper theoretically investigates spectral characteristics of the 3×2 microring resonator array, with its analytical
model developed firstly. Simulation results show that the case of the ring-bus coupling coefficient smaller than the ringring
coupling coefficient is suitable for box-like filters. After design principles are given, the optimization process are
carried out by evaluating the side lobe rejection ratio, the passband ripple rejection ratio and the roll-off coefficient of the
passband edge. The FWHM of the designed box-like filter can be adjustable in a flexible range.
Integrated optical microwave channeliser
Michael W. Austin
Show abstract
An integrated optical chip based on an array of silica waveguide Fabry-Perot filters with dielectric mirrors has been
fabricated as part of a photonic microwave channelising receiver. The channeliser is based on a vernier architecture.
Thin-film heaters on the surface of the waveguide filters enabled the resonant frequency of the filters to be tuned. Filter
3dBe bandwidths of ~1 GHz were measured.
Fiber Design and Fabrication
Fabrication and design of asymmetrical twin core fiber for passive mode-locking
Show abstract
We demonstrate the fabrication of a kind of asymmetrical twin core fiber, which is easy spliced with standard single
mode fiber. This fiber is designed to be used for passive mode-locking in fiber lasers.
Theoretical design of low-loss single-polarization single-mode microstructured polymer optical Fiber
Show abstract
A new structure of single polarization single mode (SPSM) microstructured polymer optical fiber (mPOF) is proposed
and numerically analyzed by using a full vector finite element method with anisotropic perfectly matched layers. The
cutoff wavelength of two linearly polarized states can be design by varying the structure parameters of mPOF. The
confinement loss are also numerically calculated and optimized at communication wavelength of polymer optical fiber
(POF) of 650 nm. From the numerical results it is confirmed that the proposed fiber is low-loss SPSM mPOF within the
wavelengths ranging from 0.63 μm to 0.73 μm, where only the slow-axis mode exists and the confinement loss is less
than 0.05 dB/m.
Optical Waveguide Devices II
Spectroscopic properties of Tm[sup]3+[/sup] ions in Tm[sup]3+[/sup]/Yb[sup]3+[/sup] codoped tellurite glass
Show abstract
Absorption coefficience of Tm3+ ions in Tm 3+ /Yb3+ codoped tellurite glass have been analyzed by
using the J-O theory. The J-O parameters are calculated to be Ω2 = 11.11×10-20 cm2, Ω4 = 3.5×10-20
cm2 and Ω6 = 3.6×10-20 cm2. Spontaneous radiative transition probabilities, branching ratios and
radiative life time of Tm3+ ions are also calculated, the calculation results indicate that it is difficult to
get S-band amplification through single 808 nm laser pump in this glass, this is tested by 808 nm
single wavelength pump experiment. The Yb3+ codoping with Tm3+ and energy transfer process
between them make 980 nm single wavelength pump scheme possible to get S-band amplification,
experiment results indicate that 980 nm pump energy absorbed by Yb3+ is transferred to Tm3+,
consequently, the low cost 980 nm pump scheme could make it become promising material for S-band
amplification.
Cu-Na ion exchange soda-lime glass planar waveguides and their photoluminescence
Yunqiang Ti,
Xin He,
Jian Zhang,
et al.
Show abstract
Copper ion exchange technique was used to fabricate soda-lime glass planar waveguides. Prism coupling method was
applied to measure the effective indices, and the refractive index profiles were reconstructed through Inverse WKB
(IWKB) method. Optical absorption and photoluminescence analysis were carried out as well. The emission spectra
centered at 520nm are attributed to Cu+ located in distorted octahedral sites. It was found that the ion exchange time and
temperature both play an important role in the waveguides luminescence properties. The emission spectra intensities
decrease with the ion exchange time increasing. The emission peak wavelength slightly blue shifts as the ion-exchange
time increasing as well. The emission band intensity nearly increases consistently with the ion-exchange temperature
increasing within proper ion-exchange time. Different excitation wavelengths were tested as well in order to study the
site effect on photoluminescence properties.
Variable optical power splitter based on slot waveguide
Show abstract
To meet the application demand of optical communication system, a new type of variable optical power splitter (VOPS)
based on slot waveguide by adjusting manually is proposed in this paper. The device is designed by using the principle
of optical field effect. It has an import port which provides import power, and two output ports, the power of which is
divided dynamically by changing the width of the gap between two slot waveguides. This paper can specify the
operation principle of the device, test its important technical indicators and analyze experimental datum. Experimental
results show that the device can realize light distribution of the single wavelength and multiple wavelengths and that the
power splitting ratio is dynamically tunable and the tuning range can be 1-25dB, which ensures rapid organization and
deployment of communication network.
Design of athermal all-polymer waveguide microring resonator
Show abstract
The athermal all-polymer waveguide microring resonator is realized by selecting
polymer substrate with proper thermal expansion coefficient to substitute the silicon one. The
designed results show that the maximal resonant wavelength shift is -0.0085nm and the maximal
temperature dependent wavelength shift slope is -0.0009nm/K when the temperature varies from
20°C to 65°C.
Photonic Crystal Fibers II
Ultra-flattened chromatic dispersion photonic crystal fibers with high nonlinearity for supercontinuum generation
Show abstract
We propose a novel design for photonic crystal fiber, which has flattened-dispersion, high nonlinear coefficient and low
confinement loss for supercontinuum generation. The proposed fiber needs appropriate number of design parameters.
Results show that eight-ringed photonic crystal fiber is obtained with nonlinear coefficient greater than 33W-1 km-1, and
small dispersion slope 2.00×10-3ps/nm2/km in the telecommunication window. Ultra flattened dispersion of -1.65~ 0.00
ps/nm/km and confinement loss in super low order of 10-4dB/km are simultaneously obtained ranging from 1.45μm to
1.65μm. It's shown that through numerical analysis the novel micro-structured optical fiber with small normal
group-velocity dispersion and nearly zero dispersion slope offers the possibility of efficient supercontinuum generation
in the telecommunication window using a few ps pulse. supercontinuum with 70nm-bandwidth at 1550nm is achieved
through only 150m-long fiber.
Slope-matching profile optimization of dual-concentric-core photonic crystal fiber for broadband dispersion compensation
Show abstract
Design optimization of a pure silica dual-core photonic crystal fiber for broadband dispersion compensation is proposed
to match the relative dispersion slope of the standard single-mode fiber. The influence of the three diameters of the
air-holes in the outer cladding upon the dispersive and slope-matched property is investigated and a dispersion value of
-3179.9 ps • ;nm&--1 • km--1 at 1550 nm has been predicted. The dispersion of the standard single-mode fiber, which is
187 times the length of the dual-core photonic crystal fiber, can be compensated (to within 0.12%) over the entire C band
/ (to within 0.56%) over the 100-nm broadband centered at 1550nm .
Two-mode photonic crystal fiber interferometer for temperature and strain sensing
Show abstract
A compact in-line interferometer is demonstrated by splicing a piece of two-mode photonic crystal
fiber (TPCF) between two segments of single mode fiber (SMF). The TPCF is completely homemade
and carefully simulated by finite element method based on the real cross section. It is firstly verified
that the interference occurred between LP01 and LP11even modes and the period of the interference
pattern was inversely proportional to the length of TPCF. The temperatures and strain induced
interference pattern shifts with sensitivities of -43pm/°C and -0.62pm/με are experimentally monitored.
©2009 Optical Society of America.
Spectral compression of femtosecond pulses in photonic crystal fiber with anomalous dispersion
Show abstract
We present a numerical investigation of nonlinear propagation of chirp-free femtosecond pulses at 1550-nm wavelength
in a nonlinear photonic crystal fiber (PCF) with anomalous dispersion. The PCF has a second-order dispersion of - 8.67
×104 fs2/m, third-order dispersion of 2.8 x 105 fs3/m and nonlinear coefficient of 11 W-1km-1 at 1550 nm. The simulation
results show that efficient spectral compression of unchirped ultrashort pulses is induced in PCF when the input pulse
parameters satisfy the condition 0.6< N<0.7for the soliton number N. It is found that the compressed spectral width is
strongly dependent on the initial peak power and propagation length of the incident pulse. A compression factor up to 7
can be achieved. With the PCF, efficient spectral compression can take place in the wavelength range of 1530 ~ 1570 nm
covering the C-band. This spectral-compression scheme offers much promise for laser spectroscopy, optical information
technologies and high-power fiber-laser systems.
Optical Amplifiers
Second-order effects in fiber optical parametric amplifier
Show abstract
Fiber optical parametric amplifiers (OPAs) are based on the third-order nonlinear susceptibility of glass
fibers. If two strong pumps and a weak signal are fed into a fiber, an idler is generated. Signal and idler
can grow together if pump power is high enough, and phase matching occurs. Until recently,
impressive performance of fiber OPAs has been demonstrated in different respects. However, secondorder
effects should be addressed before OPAs can be utilized in practical applications. Here we report
some of these effects, either exploiting them as in the parametric processor such as optical logic gates,
inverted and non-inverted wavelength converter, and ultra-wideband monocycle and doublet pulses
generator, or suppressing them as in the optical amplifier for WDM systems.
Multi-tap photonic microwave filter based on two-pump fiber optical parametric amplifier
Show abstract
We propose and demonstrate a novel approach to implement a multi-tap photonic microwave filter. By using a twopump
fiber optical parametric amplifier (OPA), the number of signal laser sources needed is only half of the number of
filter taps because new frequency components idlers are generated. Moreover, the free spectral range (FSR) of the
proposed filter can be changed by simply changing the wavelength spacing between the signals. In our experiment, an 8-
tap photonic microwave filter has been demonstrated using 4 signal laser sources, with FSR tuning range from 1.18 GHz
to 2 GHz which shows consistency between experimental and theoretical results.
Experimental research on secondary pulsation in an all-fiber pulsed amplifier
Show abstract
The experimental study on an all-fiber laser pulse amplifier system using homemade double-cladding Yb-doped fibers as
gain media is presented. Secondary pulse phenomenon produced in the pulse amplifier system is analyzed and
investigated. We find that the phenomenon depends a lot on the quality of splicing between different fibers and the
amplification multiple. By controlling the pump power and amplification multiples of the amplifier and trying different
splicing parameters, we can get stable high power pulse lasing output. Finally, using the Yb-doped double-cladding
fiber(YDCF) and master oscillation power amplification (MOPA) techniques, a stable all-fiber pulse amplification
system is obtained, with lasing wavelength at 1064 nm, 20 ns line-width pulses, average power of 2.4W and repetition
rate of 50kHz.
A new adaptive erbium-doped fiber amplifier
Show abstract
A new adaptive erbium-doped fiber amplifier (EDFA) is proposed. In the amplifier, an array of 1×2 optical switches is
controlled to select the optimum length of erbium-doped fiber for different input power, and meanwhile pump power is
regulated, so good adaptivity for different applications can be obtained. Simulation experiments have demonstrated that
this amplifier can get high performance. It can be applied as preamplifier and line amplifier as well as power amplifier.
Optical Devices 1
A novel FBG laser sensor based on beat frequency modulation technology
Show abstract
We propose and experimentally demonstrate a novel FBG dual-wavelength fiber laser sensor based on the beat
frequency demodulation technology. The dual-wavelength beat frequency sensing signal of about 5.224 GHz has been
obtained in a photodetector and observed by a radio-frequency spectrum analyzer (RFSA). Furthermore, by employing a
LiNbO3 modulator, the high-frequency beating signal can be tuned arbitrarily to tens or hundreds of MHz without
distortions. Thus a very cheap and low-frequency RF spectrum analyzer can be used in frequency signal detection. When
a strain is applied on the sensor, the beating signal will shift with a stain sensitivity of about (-3.92) kHz/με.
Metal-based 1X2 plastic optical fiber (POF) splitter for video over POF system application
Show abstract
A 1X2 POF splitter based on a Y-branch metal hollow POF coupler design has been developed. The device is composed
of three sections: an input POF waveguide, an intermediate hollow waveguide taper and output POF waveguides.
Simulation based on non-sequential ray tracings have been performed on the POF splitter. Low cost aluminum based
material has been used for the device substrate. Fabrication of the POF splitters are done by producing the device mold
insert using high speed CNC machining tool and short POF fibers at the input and output sections are inserted inside the
mold insert before the interfaces of the hollow waveguide taper. The POF splitter has an average insertion loss of 5.8 ±
0.2 dB, excess loss of 2.8 dB and coupling ratio of 1:1. A video-over POF system test-bed consisting of a POF video
transmitter and receiver has been constructed with a total transmission length of 10 m. The POF splitter has been tested
in the video-over POF system and shows no significant signal degradation.
Eight-channel wavelength division demultiplexer using multimode interference
Show abstract
We present a new design of wavelength division demultiplexer based on self-imaging principle in the multimode
interference (MMI) structure. We simulated an 8-channel wavelength demultiplexer with high quality factor in the
telecommunication range. The structure has been designed with multi-stage multimode interference couplers. The
principle of the design of structure can be extended to N-channel wavelength division demultiplexer. To the best of our
knowledge, this work presented for the first time in MMI structure with almost 5nm channel spacing and 2451 average
quality factor. Output wavelengths that are achieved from the first to the latest outputs are 1545nm, 1564.4nm, 1535nm,
1554.37nm, 1530nm, 1549.9nm, 1540nm, 1559.5nm, respectively. The beam propagation method is used for simulation
of this device.
Investigation of a Fabry-Perot-based optical filter for broadband multichannel communication systems
Show abstract
Based on Fabry-Perot structure, a multiple-channel filter is obtained in theory by changing the structure of spacer layers.
This paper is concerned with the design of optical filters, based on thin-film interference, for multichannel optical
communication systems with Ta2O5 and SiO2 materials for 1550 nm operation. The performance of the filter
configuration is analyzed and the numerical results of the optimization parameters, such as central wavelength, 3-dB
bandwidth, figure of merit and ripple in the passband, are reported. The variation of these parameters is also studied for
various modified filter configurations. The angular performance of the filter is investigated in terms of spectral shift of
transmittance towards shorter wavelengths. It is concluded that the width of adjacent routeways can be changed by
changing the structure of spacer layers. The variation of these parameters is also studied for adding irregularly suited
layers. The layer sensitivity of the ultra broadband multichannel thin-film-based optical filter, is thoroughly analysed.
Compact in-fiber Mach-Zehnder interferometer using a twin-core fiber
Show abstract
A compact in-fiber Mach-Zehnder interferometer comb-filter is demonstrated by splicing a section of twin-core fiber
(TCF) between two single mode fibers (SMFs). The temperature and strain induced wavelength shifts of the interference
fringes are experimentally monitored. Redshift (i.e., wavelength shifts to the longer wavelength side) is observed with
sensitivity of about 0.037 nm/°C for increased temperature, whereas blueshift (i.e., wavelength shifts to the shorter
wavelength side) is observed with sensitivity of about 0.866 pm/με for applied strain changes. This device is relatively
simple to fabricate and expected to have applications in high temperature or strain fiber optic sensors and the multiwavelength
fiber lasers.
Optical Fiber
Progress in semiconductor optical fibers
Show abstract
The properties of glass-clad fibers containing cores of phase pure and highly crystalline
silicon and germanium are reviewed. Although further optimization is required, losses of about 4
dB/m have been achieved at 3 μm and suggest that such semiconductor core fibers could be of
practical value for nonlinear and infrared applications.
The improvement of transmission properties for multi-mode fiber based on launching optical field shaping and feedback equalization
Show abstract
Recently, as the continual development of services and needs, people have a higher expectation on the optical
communication system especially the passive optical network (PON). Deciding which kind of fiber to be the optimal
media for PON is becoming a critical problem. This paper analyzed the feasibility for the applying of multimode fiber
(MMF) in the future long haul, high bit-rate, and large capacity PON, and summarized the strengths and weakness of
MMF. Then, initiating from the waveguide theory in the weakly guiding fiber and neglecting the intra-modal dispersion
as well as nonlinearity, we built a simple model for multimode fiber, based on which we made analysis, research and
comparison through simulation experiments on some performance improving techniques of MMF: offset launching,
mode size changing, ring launching and feedback equalization. The simulation results demonstrated that the combination
of field shaping and feedback equalization can obviously improve the transmission properties of MMF, because of
which, the 10Gbit/s data can travel in the MMF for more than 1km.
Wave breaking in dispersion-decreasing fiber with normal group-velocity dispersion
Show abstract
We show wave breaking (WB) can occur in a dispersion decreasing fiber with normal group-velocity dispersion
preceding the parabolic pulse formation (PPF), and the distance where it happens can be described by two equations.
Based on the transformation of a nonlinear Schr dinger equation with the typical decreasing dispersion into the form of
the uniform dispersion and "equivalent" gain, the first equation is obtained to determine the virtual WB distance. The
corresponding real distance can then be acquired from the second equation derived from the fiber dispersion distribution
function. Both the analytical results are confirmed by the numerical simulations of the two forms NLSE, and illustrated
by the chirp oscillations appeared in the pulse edges, respectively. We further demonstrate that the spectral broadening of
the pulse is quite different from that of the pulse temporal evolution during the PPF process. In the initial stage, the
spectral broadening is dominated by the expansion of ripples in the central part of pulse caused by self-phase modulation
(SPM); while in the last stage, it is dominated by the widening of sidelobe in the pulse wings caused by four-wave
mixing (FWM). These facts reveal that FWM also plays an important role in the process of PPF besides SPM while the
WB point is the very threshold that FWM begins to take effect.
Longitudinal fiber parameter measurements of pure silica core fibers based on OTDR technique
Show abstract
A simple technique for measuring fiber parameter distribution of the pure silica core fiber using a conventional OTDR is
proposed. This technique is based on the relationships among fiber parameters and the bidirectional OTDR technique.
The fiber parameter distributions are successfully evaluated for a silica core fiber link.
Optical Devices II
Two- and three-dimensional studies of a silicon-based chromatic dispersion compensator
Show abstract
In this work, we demonstrate two- and three-dimensional (3D) simulations of an active silicon-based photonic crystal
chromatic dispersion compensator utilizing the free carrier dispersion effect. The device has a low power consumption
of 114nW and its intrinsic device modulation speed is predicted to function at 40.5MHz. Due to the device architecture,
simulation must be carried out in 3D so as to fully encapsulate the effects of the photonic crystal contributions in the
active silicon. The novel device allows waveguiding and electrical transport to be individually tailored to a large extent.
Optimal design of cascaded long-period waveguide grating equalizer for broadband Er-Yb co-doped phosphate glass waveguide amplifiers
Show abstract
Broadband integrated Er-Yb codoped phosphate glass waveguide amplifier based on cascaded long-period waveguide
grating gain-equalizer is proposed. The proposed cascaded long-period waveguide grating gain-equalizer consists of
some different long-period waveguide grating filtering unit cells, and each cell can suppress certain peak gain at a
specific wavelength. The intrinsical gain spectrum of amplifier is obtained by solving a set of rate and power
propagation equations with overlapping integral-Runge Kutter method. The effect of the transmission spectrum of the
proposed cascaded long-period waveguide grating on the flattening gain of Er-Yb codoped phosphate glass waveguide
amplifier is discussed. The transmission function of the cascaded long-period waveguide grating filter is obtained.
Low-loss bend-bend coupler for an ultra-small microring resonator based on Si nanowires
Show abstract
This paper presents a bend-bend coupler for an ultra-small microring resonator based on Si nanowires in order to reduce
the mode-conversion loss at the coupling region. And relatively large amplitude coupling coefficient and low coupling
loss are achievable due to the long coupling length of the bend-bend coupler.
Poster Session
The dispersion and dispersion slope characteristics of the fiber gratings fabricated in tapered fiber
Show abstract
A novel method to compensate dispersion and dispersion slope at the same time by using fiber Bragg grating
written on the tapered core fiber has been presented. The fabrication method about this kind of tapered core fiber has
been realized by precisely controlling the fiber's diameter during the process which is drawing the preform into optical
fiber. The fiber grating written on this kind of fiber has parameter as 3dB bandwidth 0.861nm. Its dispersion value is -
1159ps/nm (within 0.8nm bandwidth), and the dispersion slope is -1.3 ps/nm2. These characteristics of the grating make
it can be used in high speed optical fiber communication systems which need the dispersion and dispersion slope be
compensated at the same time.
Study on characteristics of optical bistable devices based on fiber Bragg grating
Show abstract
The simulation model to bistable characteristics of grating is established by numerically solving the nonlinear coupledmode
equations of Fiber Bragg Grating using 3-stage 4-order semi-implicit Runge - Kutta method. The impact of the
grating parameters and operating point on S-shaped hysteresis loop parameters is researched. The results show that the
area of S-shaped hysteresis loop, bistable operating condition, bistable threshold and dynamic range can be adjusted by
changing the operating wavelength and grating parameters, such as grating length, grating apodization and average
refractive index modulation depth of grating.
Multiwavelength erbium-doped fiber ring laser employing Fabry-Perot etalon
Show abstract
We propose a multiwavelength erbium-doped fiber (EDF) ring laser using a Fabry-Perot etalon inside the ring cavity
with optimal fiber length to satisfy the least common multiple number for generating multiwavelength at room
temperature.
Supercontinuum generation in tapered fibers
Show abstract
Here we demonstrate a supercontiuum spectrum generated in a tapered fiber pumped by a Ti sapphire laser with 130fs
pulse width at 800nm centre wavelength. The tapered fiber with the diameter of 1.25μm and the length of 16cm was
made by using a tapered machine. The supercontiuum range is from 500nm to 900nm. We simulated the
supercontinuum with the nonlinear Schrodinger Equation and discussed the affecting factors. In some conditions, the
experimental results are agreed very well with the theoretical analyses.
Pole-zero diagram approach to the design of Michelson Gires-Tournois interferometer interleaver
Show abstract
A novel and simple design method based on pole-zero diagram is proposed for optical interleaver based on Michelson
Gires-Tournois interferometer (MGTI) with arbitrary cascaded reflectors. Digital filter model which is equivalent to the
MGTI optical interleaver is derived firstly. Then on the basis of it, the transfer functions of two output ports of the
interleaver are simplified and all the design parameters of the interleaver can be obtained conveniently by the use of the
mature design principle of elliptic filter and pole values. The two output spectrums obtained has the wide flat passband
(and stopband) width and high isolation simultaneously. Compared with other existing design methods, the proposed
method is simpler and more efficient, especially for interleavers with GTE composed of much more reflectors. Design
examples of the interleaver with different cascaded G-T etalon structure are given.
Frequency response of fiber-optic hydrophone with a novel mechanical anti-aliasing filter of side cavities
Show abstract
We demonstrate a novel fiber-optic hydrophone with a mechanical anti-aliasing filter of side cavities. The amplitude and
phase frequency response properties are presented with an acoustic equivalent circuit. Theoretical results show that the
hydrophone has very flat low frequency response, and can greatly attenuate high frequency sound. The response curve
has three resonant frequencies and an inverse resonant frequency, which is induced by the side cavities and contributes
much to the high frequency attenuation. The hydrophone is tested in a standing-wave tube filled with water, and the
measured frequency responses accord well with the theoretical results.
Widely tunable L-band Brillouin fiber laser incorporating a bismuth-based erbium-doped fiber
Show abstract
A widely tunable single-wavelength Brillouin fiber laser (BFL) incorporating a bismuth-based erbium-doped fiber (Bi-EDF)
is proposed. The 52 cm-long highly erbium-doped Bi-EDF provides broadband gain extending from the C-band (1525-1565
nm) to the L-band (1565-1625 nm). In experiment, the BFL operates in a range from 1555 nm to 1632 nm, which is the
widest to the best of our knowledge. The proposed BFL is an attractive narrow linewidth laser source on the L-band, which
has many potential applications, such as in slow light, coherent communication, and interferometric sensing.
Femtosecond pulse compression in hollow-core photonic bandgap fibers
Show abstract
Compression of chirped free femtosecond pulses in hollow core photonic bandgap fibers is investigated numerically. The
results show that intrapulse stimulated Raman scattering can improve the quality of the compressed pulse. Positive
third-order dispersion is the main limitation on the compression of the femtosecond pulse. However, the combined effect
of the intrapulse stimulated Raman scattering and the negative third-order dispersion can form still shorter pulses than is
possible with intrapulse stimulated Raman scattering alone. We also investigate the influence of width and peak power
of input pulse on pulse compression.
Absolutely single polarization photonic crystal fiber based on a structure of sub-wavelength hole pitch
Daru Chen
Show abstract
An absolutely single polarization photonic crystal fiber (ASP-PCF) with periodic structure of sub-wavelength hole pitch
is proposed. Circular air holes and elliptical air holes with diameters smaller than the operation wavelength are employed
in the fiber cladding area and the fiber core area, respectively. Calculation results show that both ultra-high birefringence
and ASP operation are achieved over a large wavelength range covering the fiber optical communication window from
1300 nm to 1600 nm for the proposed ASP-PCF. The ASP operation bandwidth can be further enlarged based on the
optimized designs.
Study and fabrication of add/drop filter based on Bragg gratings reflection coupler
Show abstract
Double-grating coupler based on two fiber Bragg gratings(FBGs) has the advantages of compact structure and enhanced
filtering efficiency. The influences of different gratings' position in the coupling region and grating length on the
filtering spectra were investigated based on the unified coupled-mode theory. The results show that, the coupling region
on the left of the graing mostly affects the drop channel characteristic;the length of the grating mostly affects the drop
efficiency;the transmission characteristic is best with the whole length of the coupling region Lc integral multiple of
coupling lengthπ /(2Kf ) .A coupler with uniform coupling region making of two photoconductive fibers was fabricated
by improved fused taper technology,then two Bragg gratings were written in the coupling region with 248nm ultraviolet
laser, and a grating reflecton coupler with maximum drop reflectivity 20dB and bandwidth 0.8nm was achieved.
Growth of ultraviolet-induced H[sub]2[/sub]-loaded long period fiber grating immediately after fabrication
Show abstract
The growth of long period fiber grating written in H2-loaded fiber within one hour immediately after fabrication was
measured and analyzed. Fast deepen on difference of refraction index was obviously observed in all the experiments,
but the peak wavelength to time and cross-coupling coefficient to time curves are fitted better in exponential decay
function than power function, and suggest a same variation pattern in difference of refraction index.
Finite element analysis of the InP nano inner cladding fiber
Show abstract
We proposed that nanomaterials can be used to change the characteristics of standard fibers. After two stages, preform
fabrication and fiber drawing, a novel inner cladding fiber with InP nano thin film has been successfully fabricated by
the means of MCVD. The thickness of the InP film is about 60nm. The electric field distribution is simulated through the
the finite element method. The simulation result indicates that the InP nano film can confine the electric distribution in
the core. In addition, it is calculated that the effective refractive index is 1.585.
Optimal design of birefringent Gires-Tournois optical interleaver
Show abstract
A new type BGTI with only one GTI is designed first and it could reduce PMD greatly and has much better temperature
stability compared to traditional BGTI, the channel isolation rate of single-stage structure is not enough and result in
crosstalk increasing and SNR reducing. To improve isolation rate, two cascaded BGTI are used to realize the second
filter. Simulation and experiment results show that isolation rate is improved, the bandwidth is remained and PMD also
reaches requirement design, successfully optimizing the system performance.
Optimal control of light storage in atomic ensemble based on photon echoes
Show abstract
This paper presents a simple quantum memory method for efficient storage and retrieve of light. The technique is based
on the principle of controlled reversible inhomogeneous broadening for which the information of the quantum state light
is imprinted in a two-level atoms ensemble and recalled by flipping the external nonuniform electric field. In present
work, the induced Stark shift varied linearly with position, and a numerical analysis for this protocol has been studied. It
shows that the storage efficiency can nearly reach 100% with a large enough optical depth, and the optimal broadening
for a given pulse width is also analyzed.
Fiber Bragg grating sensors interrogation system using arrayed waveguide gratings demultiplexer
Show abstract
A Fiber Bragg Grating (FBG) sensor interrogation system using Arrayed Waveguide Gratings(AWGs) demultiplexer
is designed and studied theoretically and experimentally. By using a temperature tunable arrayed waveguide grating
(AWG), the center wavelength of the FBG sensor is successfully interrogated, with the linear temperature dependence
of the AWG transmission wavelengths. Initial results show that the proposed wavelenght interrogation technology using
AWG demultiplexer could potentially offers a low-cost, compact, and high-performance solution for the interrogation of
FBG distributed sensors and multisensor arrays.
Bending sensor with tilted fiber Bragg grating interacting with multimode fiber
Show abstract
A new type fiber bending sensor based on a tilted fiber Bragg grating (TFBG) interacting with a multimode fiber (MMF)
is presented. The sensing head is formed by insertion of a small section of MMF between single-mode fiber (SMF) and
the TFBG. The reflection light from this sensor head includes two parts, i.e., the reflected Bragg mode and cladding
modes. The latter were first coupled from the core mode to counter-propagating cladding modes by the TFBG and then
coupled back into the core as a function of the MMF. The power of the cladding modes changes as the fiber is bent while
the Bragg one keeps unchanged. The average reflective power in the cladding modes decreased with the increase of
curvature. The measurement range of the curvature from 0m-1 to 2.5m-1 with a measurement sensitivity of -802.4nW/m-1
is achieved.
C+L band multi-wavelength fiber laser based on cascaded semiconductor optical amplifier
Show abstract
In this paper, a multi-wavelength fiber laser based on cascaded semiconductor optical amplifier (SOA) was proposed
by using a high birefringence fiber loop mirror (Hi-Bi FLM) as wavelength filter. The 0.6nm homogeneous
broadening line-width of the SOA enabled laser oscillation with WDM ITU-grid spacing possible. With this
configuration, SOAs with small signal gain peak wavelengths at 1540nm and 1510nnm were cascaded as gain
medium in the laser for laser oscillating in C+L band. The output results with different driving current of SOAs were
obtained and compared experimentally. The wavelength spacing of this laser was controlled by using different
lengths of Hi-Bi fiber. By using 5.9m Hi-Bi fiber in Hi-Bi FLM, 100GHz wavelength spacing was obtained. The
output 26 wavelengths within 6dB bandwidth spacing on 100GHz were obtained. These multi-wavelengths covered
C+L band and were centered on 1566.599nm. The line-width of each channel was 0.102nm with more than 25dB
SNR. All these channels can be continuously tuned over 50GHz by controlling the polarization controller in Hi-Bi
FLM. Output of multi-wavelength fiber laser with only one SOA as gain medium was also presented for comparison.
Keywords: multi-wavelength, fiber laser, semiconductor optical amplifier, cascaded, C+L band, high birefringence
fiber loop mirror, 100GHz, continuously tunable, homogenous broadening, wavelength-division multiplexing
A novel technology to generate microwave signal based on multiple-frequency Brillouin fiber-ring laser
Show abstract
A novel multiple-frequency Brillouin fiber-ring laser utilizing a ring cavity is proposed and experimentally
demonstrated. And eight wavelengths can be obtained from this laser. Based on this laser, the mechanism for generation
of high frequency microwave signal is proposed and partly realized. To confirm the feasibility of this method, 11GHz
microwave signal is obtained by the experiment.
Novel technique for the measurement of photonic crystal fiber numerical aperture properties
Show abstract
In this paper, the numerical aperture (NA) of photonic crystal fiber (PCF) is measured by a system with spectrometer,
and high-precision results are obtained. The spectrometer can record the light intensity of different wavelengths. It
overcomes the limitation that the traditional measurement can only measure the NA in some fixed wavelengths. We get
the NA at any wavelength in 500nm~900nm range, which is determined by light source and spectrometer. Therefore, the
parameters related with NA can be better studied, such as: the mode field area, cut-off wavelength and so on. The
characterization of PCFs can be better represented too. The measured results are compared with theoretical calculation
value, and they agree with each other very well. According to the measured NA, the mode field area of sample fiber is
calculated and compared with simulation results calculated by fast-vector-method.
Influence of cores' shape on coupling length of dual-core fiber
Show abstract
The deviation of cores' shape in dual-core fiber may affect the coupling characteristics between the two cores. For the
same given cores' area in three kinds of dual (circular, elliptical, egg-shaped) core fiber, the relationship of the coupling
length with the cores' shape is calculated at different wavelength It is found the coupling length of dual-circular-core
fiber is the longest and dual-elliptical-core fiber is the shortest while dual-egg-shaped-core fiber is in the middle.
Switchable dual-wavelength fiber laser based on PCF Sagnac loop and broadband FBG
Show abstract
Switchable dual-wavelength fiber laser with photonic crystal fiber (PCF) Sagnac loop and broadband fiber Bragg grating
(BFBG) at room temperature is demonstrated. By adjusting the polarization controller (PC) appropriately, the laser can
be switched between the stable single- and dual-wavelength lasing operations by exploiting polarization hole burning
(PHB) and spectral hole burning effects (SHB).
Refractive sensitivity of mechanical long-period fiber grating in side-hole fiber
Show abstract
The refractive index sensor for use of mechanically induced long-period fiber grating (MLPG) in a side-hole singlemode
fiber is proposed. The principle of operation is based on using of a long-period grating that is made by pressing a plate
with periodic grooves against a short length of side-hole fiber. The strength of the resonant peak is tuned by adjusting the
pressure applied on the side-hole SMF. The resonance wavelengths are shifted as the two side-holes of the fiber core
were filled with the different the refractive index liquids. The resonant wavelength of 1588.6 nm has a total blue shift of
approximately 12.2 nm for refractive index ranging from 1.35 to 1.43. The results show that it is more sensitive than that
of the conventional SMF long-period fiber gratings.