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- Front Matter: Volume 7134
- Photonic Crystal Fibers I
- Fiber Lasers and Amplifiers
- Optical Fibers I
- Fiber Bragg Gratings
- Best Student Papers
- Optical Components I
- Specialty Fibers
- Optical Components II
- Photonic Crystal Fibers II
- Optical Buffer and Signal Processing
- Optical Fibers II
- Silicon Photonics
- Nonlinear Signal Processing
- Optical Switches
- Polarization Effects
- Fiber Sensors
- Fiber Lasers
- Optical Devices
- Microstructured Fibers
- Fiber Ring Lasers
- Optical Filters
- Fiber Gratings
- Nonlinear Effects
- Poster Session
Front Matter: Volume 7134
Front Matter: Volume 7134
Show abstract
This PDF file contains the front matter associated with SPIE Proceedings Volume 7134, including the Title Page, Copyright information, Table of Contents, Introduction (if any), and the Conference Committee listing.
Photonic Crystal Fibers I
Better photonic crystal fibres
Show abstract
The development of optical fibers with two-dimensional patterns of air holes running down their length has reinvigorated
research in the field of fiber optics. It has greatly - and fundamentally - broadened the range of specialty optical fibers,
by demonstrating that optical fibers can be more 'special" than previously thought. Applications of such special fibers
have not been hard to find. Fibers with air cores have made it possible to deliver energetic femtosecond-scale optical
pulses, transform limited, as solitons, using single-mode fiber. Other fibers with anomalous dispersion at visible
wavelengths have spawned a new generation of single-mode optical supercontinuum sources, spanning visible and near-infrared
wavelengths and based on compact pump sources. A third example is in the field of fiber lasers, where the use
of photonic crystal fiber concepts has led to a new hybrid laser technology, in which the very high numerical aperture
available using air holes have enabled fibers so short they are more naturally held straight than bent. However,
commercial success demands more than just a fiber and an application. The useful properties of the fibers need to be
optimized for the specific application. This tutorial will describe some of the basic physics and technology behind these
photonic crystal fibers (PCF's), illustrated with some of the impressive demonstrations of the past 18 months.
A novel design of highly negative dispersion photonic crystal fibers with central index dip
Show abstract
A highly negative dispersion photonic crystal fibre with less germanium doped core and central index dip is numerically
investigated by fully vectorial finite element method. By adjusting the pitch, the depths and radius of the central index
dip and the diameter of six small air holes in the third ring, Highly negative dispersion value (-1325.5ps/nm.km) and
large mode effective area (71.4um2) DCPCF around the wavelength of 1.55μm is obtained.
Fiber Lasers and Amplifiers
High-concentration erbium-doped fiber-based short cavity ring lasers
Show abstract
A high concentration silica host Erbium Doped Fiber with Bismuth-Gallium-Aluminum co-doped was fabricated. The
absorption coefficient of this fiber was up to 19dB/m at the wavelength of 980nm and 42dB/m at 1530nm. Ring structure
lasers with different fiber lengths were presented. Their output characteristics were measured and analyzed.
Temporal characteristics of a high-power erbium-doped fiber ring laser
Show abstract
The temporal characteristics of a fiber ring laser are reported. The laser has a simple configuration, which contains
an Erbium-doped fiber amplifier (EDFA), a polarization controller (PC) and a coupler. The EDFA has a high saturation
power of 27dBm to provide the gain in the cavity. The PC is used to control the polarization state of light. A 99/1
coupler is used to extract the laser output. There is no filter in the cavity to confine the spectrum of the laser. The simple
laser configuration can operate in different temporal modes with different pump power. In the self mode locking state,
the repetition rate is equal to the inverse of the round trip time of the cavity. The repetition rate of the laser can be
increased by increasing the pump power of the EDFA. This self mode locking phenomena is due to the homogeneous
gain medium in the cavity, rather than the nonlinear effect in the cavity. The nonlinear effect can suppress the self mode
locking phenomena by inserting a short length highly nonlinear fiber in the laser cavity.
Radiation effect on EDFA for inter-satellite optical communication on low dose orbits
Show abstract
The erbium doped fiber, optical isolator and WDM coupler, which are three key optical components of commercial
erbium-doped fiber amplifier (EDFA), are radiated to the radiation dose of 5krad by electron. The radiated erbium-doped
fiber (EDF) make the output power of EDFA come down 0.5dB when the input power is between -12dBm and-5dBm.
The NF climb up 1dB. However, the peak wavelength changes little. The radiation experiment results also show that the
deterioration of the optical isolator and WDM coupler can be neglected at the dose of 5krad. In order to assure the
accuracy of analysis, the recovery experiment has been done to correct the radiation effect on the EDFA. The results
indicate that if optical communication systems have enough redundancy, the EDFA can be used on the low dose orbits
without any radiation protection for inter-satellite optical communication.
Temperature dependence of fluorescence in erbium-doped silica fiber
Show abstract
The temperature dependence of fluorescence in erbium-doped silica fiber between ~-30 and ~150°C is discussed.
980nm pumping configuration is used in our experiment. 1450nm and 1531nm wavelengths are chosen to calculate the
FIR (fluorescence intensity ratio) at the first time instead of the mostly used wavelengths 525nm and 550nm. It shows
that as the temperature increases, the fluorescence intensity increases obviously at short wavelengths but changes a little
at long wavelengths. The temperature coefficient can achieve ~0.023dB/°C, and its resolution is improved as the
temperature decreases. Because there are many effects in our experiments, so it shows a deviation from the behavior of
simulation.
Advanced topics on Er- and ErYb-doped fibers for fiber amplifiers and lasers
Show abstract
Development of Er and ErYb doped fibers for high performance Er-doped fiber
amplifiers (EDFA) and high power fiber lasers is reviewed. Fiber design optimization for
applications including wide flat gain spectrum, and high power conversion efficiency are
discussed. Major parameters such as fiber gain spectrum consistent and uniformity for volume
production are presented. In addition, some of nonlinear effects in EDFA for modern optical
communication network will be discussed.
EDFA gain-flattening based on the cascade of step-changed LPGs
Show abstract
By analyzed the two-step cascaded step-changed LPGs which have been already used as band filters for flattening the
gain of EDFAs, an improved method of introducing three or more steps cascade has been advanced in order to optimize
the transmission spectra of the filters. The calculation and simulation of the cascaded LPGs' transmission spectra are
given. The simulation results show that the transmission spectral profile can be tailored into an adoptive shape and
simultaneously the effective bandwidth would become wider by adjusting the two parameters, the length and the index
perturbations of each segment in cascade. This method is demonstrated to be an effective way to flatten the gains profile
of EDFAs.
Optical Fibers I
New bend insensitive fiber products enabled deep penetration in MDU and FTTP inside wiring
Show abstract
The emergent of True-Bend-Insensitive-Fiber product is a major triumph for the fiber optics
industry. By defining the requirements and understanding the trade-offs in optical performance, large-scale
manufacturing compatibility, standards compliance, mechanical performance, compatibility with field
equipments and installation procedures will be critical to identify the most cost effective alternative.
Bend insensitive fibers for FTTH and MDU
Show abstract
As deployment of fiber to the home (FTTH) within multiple dwelling units (MDUs) is growing, more technicians will be
involved in the deployment of optical drop cables, and there is a desire to use craft and practice similar to what is used
for copper cables. We introduce a solid bend insensitive fiber in this application that is backwards compatible to G.652D
fiber, and has macrobending, splice loss and system performance to meet the very demanding conditions of these
applications. A closer look at the demands of this environment has made it necessary to re-evaluate reliability in these
critical applications. We apply the Power Law Model to predict reliability in these demanding applications, and provide
experimental evaluation of the model through testing on optical fibers and cables. It will be shown that bends and tension
need to be considered together when evaluating the reliability of the passive optical plant.
Dispersion of the nano-InP doped fiber
Show abstract
We propose that nanomaterials can be used for fibers. A novel nano-InP doped fiber has been fabricated by the method of
modified chemical vapor deposition (MCVD).It has been measured that the doping concentration is 0.1%. The
relationship between refractive index and the wavelength is obtained by fitting experimental data to Sellmeier equation.
Dispersion of the fiber has been calculated in the wavelength range 1.2-1.6μm. As the wavelength varies from 1.2μm to
1.60μm, dispersion parameter D increases but is always negative. It has found that the dispersion of nano-InP doped
fibers is strongly changed compared to standard single-mode fibers, due to the nano-InP dopant which lead to a higher
refractive index difference.
Fiber Bragg Gratings
The design and fabrication of optical fiber Bragg grating filter with dual-bandpass pair by phase sampling and phase shifts
Show abstract
Phase sampling and phase shift techniques are introduced in a uniform fiber Bragg grating (FBG) structure to achieve a
multi-bandpass filter with ultranarrow transmission bandwidth. A pair of dual-bandpass transmission windows are
opened at 1542.32, 1542.36, and 1542.66, 1542.71 nm, respectively. The channel spacing between the pair can be
designed by the phase sampling period, as well as the wavelength spacing in the dual-bandpass can be controlled through
the phase shift length. This new kind of bandpass structure can be applied in the ultranarrow filtering in multi-channel,
multi-wavelength distributed feedback Bragg lasing, photonic generation of microwave signal etc.
Recent advances in the design and fabrication of high channel-count fiber Bragg gratings
Show abstract
We introduce our recent progresses in the design and fabrication of the high channel-count fiber Bragg grating (FBG).
We theoretically and experimentally demonstrated the phase-only sampled FBG with channels up to 81, which could be
used as the dispersion compensator, the simultaneous dispersion and dispersion-slope compensator, respectively.
Moreover, we have presented a novel method for multi-channel FBG design, which enables us to design any kind of
multi-channel FBGs where the amplitude or the spectral response of each channel could be either identical or non-identical.
As an example, a novel design for a multi-channel FBG with asymmetrical triangular reflection spectrum has
been demonstrated.
Temperature insensitive packaging of FBG based on a flat diaphragm and an L-shaped lever
Show abstract
A fiber Bragg grating (FBG) temperature insensitive packaging scheme based on a flat diaphragm and an L shaped lever
is presented. The curve where the L shaped lever contacts the diaphragm is a segment of an Archimedes spiral, which is
used to reduce the temperature responsivity. Because the thermal expansion coefficient of the quartz-glass L shaped
lever and the steel sensor shell is different, the temperature effect is compensated for by optimizing the dimension
parameters. Theoretical analysis is presented, and the experimental results show that a low temperature responsivity of
2.8pm/°C are achieved.
Spectral self-imaging phenomena in binary phase-only sampled fiber Bragg gratings
Show abstract
The spectral self-imaging phenomenon is observed in binary phase-only sampled fiber Bragg gratings (SFBGs) using
numerical simulations. Integer and fractional Talbot effects are obtained under conditions of Talbot effect. The
characteristics of the Talbot spectrum in terms of channel spacing and the group delay from the phase-only sampled
FBGs are discussed.
Expression of reflection-peak wavelengths of arbitrary chirped and sampled fiber Bragg gratings
Show abstract
We present an analytical expression for sampled fiber Bragg gratings (SFBGs) with arbitrary chirps in sampling function
or grating period or combination of both. The relationship among the wavelength of each channel, the chirp coefficient
of the sampling and the grating period, and the total length of the grating is explicitly given. Specifically, the chirped
sampling function is first expanded into a new function using Fourier theory; the equivalent local Bragg period is then
obtained to derive the expression of the reflection peak wavelength. The overall wavelength position is obtained by
summation of both contributions from sampling chirp and the grating chirp. The calculated results based on the analytical
expression are examined with the conventional numerical results, which are found to be in excellent agreement.
Research on fiber sensor demodulating technique using tilted fiber Bragg gratings
Show abstract
Tilted fibre Bragg grating (TFBG) belongs to short-period gratings family; there is core mode and a lot of
cladding modes in the transmission spectrum. According to the special structure and coupling characteristic of the
TFBG, we propose a novel method of edge filter linear demodulation using tilted fiber Bragg gratings in a fiber
sensor system. The results show that the widely linear range of katabatic edge (1505nm~1535nm) and an
assurgent edge (1545nm~1565nm) can be used in edge filtering; the thermal characteristic of the core mode and
cladding modes is similar to FBG's. Therefore, it can compensate dynamically the temperature shift of the FBG
and the effect of temperature noise on the strain or other sensing signals is eliminated. The advantages of this
simple system are an all-fiber design, quasi static and dynamic operation, high stability and lower cost.
Best Student Papers
Continuously tunable microwave photonic filter based on high-birefringence linearly chirped grating
Show abstract
A continuously tunable, coherence free microwave photonic filter is proposed and experimentally demonstrated. The
filter is based on a high-birefringence linearly chirped fibre Bragg grating (Hi-Bi LCFBG) as the tuning component. The
filter response tunability is realized through changing the differential group delay of the Hi-Bi LCFBG by applying
gradient tension or adjusting the operating wavelength. Free spectral range tuning by 1.11 GHz with about 40 dB notch
rejection is achieved.
1.5um correlated photon pair generation in high nonlinear microstructure fibre
Show abstract
We realize the correlated photon pair generation at 1.5μm by spontaneous four-wave mixing in high nonlinear
microstructure fibre with a length of 25m, showing that high nonlinear microstructure fibres have great potential in
bright, high efficiency and compact sources of correlated photon pairs at 1.5μm.
Design of multimode interference coupled polymer rectangular ring resonators with air trench assisted mirrors
Show abstract
This paper presents a design for rectangular ring resonators based on low-index polymers operating at an 850 nm
wavelength. Multimode interference couplers are used to enable signal splitting and combining and air trench assisted
90° mirrors are used as beam turning elements. 3D full-vector, 2D FDTD and parameter models are combined to
simulate the ring resonator design. This design, suitable for spectral shaping, achieves a FSR of 0.29 nm, a FWHM of
0.066 nm and an on-off ratio of approximately 20 dB.
A novel strain sensor based on a pair of fiber Bragg grating comb filters
Show abstract
A pair of fiber Bragg grating (FBG) comb filters with different channel-spacings are
designed and fabricated to measure strain. The reflection peaks of one comb filter shift
when the strain changes. And the other comb filter is used as calibration standard. The
two comb filters have different channel-spacings, 1.00 nm and 0.95 nm, which can be
regard as the structure of vernier caliper. In our experiment, the strain resolution is about
41.7 με, with low demand of the demodulation devices. And it could be greatly improved
further in terms of Gaussian fitting technology of the peaks' intensity.
The cascadable recirculating buffer based on nonlinear polarization rotation in a semiconductor optical amplifier
Show abstract
Optical buffer is an important component in optical switching and optical signal processing. In this paper, we present a
novel all-optical buffer based on nonlinear polarization rotation induced by injection current of semiconductor optical
amplifier. With Mueller matrix, we theoretically investigate the change of polarization state induced by nonlinear
polarization rotation in semiconductor optical amplifier. The operation of the proposed optical buffer at 2.5Gb/s is
experimentally setup. The loading and reading operations with 1024bit with this optical buffer are demonstrated.
Polarization maintenance is taken into account to give the optimum operation condition
Total internal reflection type echelle grating demultiplexer based on amorphous silicon nanowire platform
Show abstract
In this paper we present measurement results of an ultracompact echelle-grating demultiplexer based
on silicon-on-insulator nanowire platform, in which we introduced a total internal reflection design of
the grating facets to improve the diffraction efficiency. An average increase of the diffraction
efficiency with 3.7dB is observed for the 3 channels compared to a normal design.
Optical Components I
Slot-based athermal silicon arrayed-waveguide grating (AWG)
Show abstract
A slot waveguide structure is used in the part of arrayed waveguides in AWG instead of silicon waveguides. It is filled
with high negative thermo-optic coefficient polymer in the narrow slot. The arrayed slot structure can remarkably reduce
the center wavelength shift when the temperature changes. In this study, we use the polymer WIR30-490 and ZP49 to be
filled in the slot. The thermo-optic coefficients of WIR30-490 and ZP49 are negative, and have the same order of
magnitude with silicon. In our simulations, by adjusting several variables of the slot structure, such as the width of the
slot between the pair of silicon wires, the width of the silicon waveguide, and the height of the silicon waveguide, we can
get the athermal condition of AWG for each polymer. Even if there is an acceptable error on fabrication, temperature-dependent
center wavelength shift of AWG can still be reduced down to 1 pm/°C. It makes the fabrication of athermal
silicon AWG possible.
Phenomenological model with application for polarization-sensitive semiconductor optical amplifiers
Show abstract
We introduce a phenomenological model to describe polarization-sensitive SOAs which is composed of a partly linear
polarizer, a retarder, and a polarization independent amplifier. It shows that any input optical vector of signal will first be
partly linearly polarized, then rotate around S1-axis of the Poincaré sphere for θ, and finally be amplified equably. Then we
investigate and experimentally demonstrate the relationship between polarization rotation (PR) and mode gains. We further
obtain two necessary conditions for the valuable orthogonal polarization rotation (OPR), and then perform a power-equalized
OPR by optical-electric synchronous control of the SOA. The polarization duration time is ~10 ns which is applicable to
high-speed polarization state generation.
A new type of mode power characteristics of extremely short external cavity semiconductor laser
Show abstract
In this paper, the total output power features and the mode power characteristics of the extremely short external cavity
semiconductor lasers (ESECSLs) have been investigated experimentally and theoretically, and a new type of variation of
ESECSL's mode power is reported. The results show that with the variation of the external cavity length at the order of
lasing wavelength, the total output power and the mode power of ESECSLs will hop periodically, and the different mode
presents diverse power characteristics. Especially, some modes, locating at the material gain center of ESECSL, present
unique double peak characteristics. Moreover, the primarily theoretical simulations and the physics explanation about
these double peak characteristics have been given. The theoretical simulation results agree well with the experimental
results. These new type characteristics of ESECSL's mode power may be useful in improving the sensitivity of all-optical
sensors and developing the new type of optical data read-write head.
Ultra-wideband pulse generation using turbo-switches
Show abstract
We propose and experimentally demonstrate a novel method for generating ultra-wideband (UWB) monocycle pulse by
exploiting a turbo-switch which consists of two reflective semiconductor optical amplifiers (RSOAs). By adjusting the
currents applied to both RSOAs, the monocycle pulse is realized due to the gain overshoot induced by the turbo-switch.
The polarity inversed monocycle pairs and the UWB doublet pulse train are numerically realized by cascading turboswitches.
Specialty Fibers
High bandwidth specialty optical fibers for data communications
Show abstract
Perhaps the most common specialty optical fiber is HCS hard polymer clad silica fiber. It was invented almost 30 years
ago for transmitting laser light to initiate explosives in mining industry and later adapted to be used in a variety of new
applications, such as data communications. The most typical HCS fiber typically consists of a 200 μm pure silica glass
core, a thin coating of low refractive index hard polymer as the cladding, and an ETFE buffer. This design enables the
"crimp-and-cleave" technique of terminating and connectorizing fibers quickly and reliably. Its greater glass diameter
also renders greater robustness allowing the fiber to endure greater forces during installation. Due to its larger core size
and high numerical aperture (NA), the fiber can be used with a plastic connector and low cost LED transmitter that can
greatly reduce the system cost. It can also be used at higher temperature and humidity conditions than standard optical
fibers coated with telecommunications grade acrylate material.
As applications evolve and require greater bandwidth and/or performance over a greater distance, the challenge now is to
develop specialty optical fibers with significantly greater bandwidth-length product while maintaining all other
characteristics critical to their ease of use and performance. As a response to the demand, two new fiber types have been
designed and developed as higher bandwidth versions of the original HCS fiber. In this paper, we will discuss some of
the main design requirements for the fibers, describe in detail the two designs, and present the results of fiber
performance.
Optical Components II
Linearity of the optical micro-resonator-based modulators
Show abstract
Linearity of the micro-resonator-based modulators for analogue modulation in terms of the spurious free
dynamic range is quantified. Some design strategies and operation techniques are presented to improve the
linearity of these devices.
Design and fabrication of SU-8 polymer-based micro-racetrack resonators
Show abstract
By using small SU-8 polymer ridge waveguides, compact micro-racetrack resonator (MRR) add-drop filters are
presented. This used small ridge waveguide has an air-cladded SU-8 polymer core (n~1.573) on a SiO2 buffer (n~1.445)
so that the bending radius could be as small as ~102μm. Considering the resolution limitation of a regular UV-lithography
process, the gap in the coupling region of the present MRR in our design is no less than 1.0 μm. In order to
enhance the coupling between the access optical waveguide and the micro-racetrack, narrow optical waveguides are used
in the coupling regions. Meanwhile, wide optical waveguides are used in the bending sections to have a small bending
radius. And a single-side taper is used to connect these two sections with different widths so that the gap width is kept as
small as 1.0 μm in the whole region. With a regular UV lithography process, the designed micro-racetrack resonator
(MRR) add-drop filters are fabricated. The measured propagation loss for straight waveguides is about 0.1dB/mm and
the measured spectral responses of the through/drop ports show a Q-factor of 8000.
Photosensitive terpolymer based on PFS:PFOA:GMA monomers for optical communications
Show abstract
A photosensitive terpolymeric composition suitable for practical waveguide devices is provided. The terpolymer was
produced from pentafluorostyrene (PFS), perfluoro-n-octyl acrylate (PFOA), and glycidyl methacrylate (GMA). We
present a fabrication process where the device structure utilizes the same class of material for the core and cladding
layers and it was fabricated without a plasma etching process. We also present simulation results that show good
agreement with measured data and which thus permit to optimize the device performance. Based on the developed
material and process; a 16-channel arrayed waveguide grating (AWG) multiplexer with excellent performance has been
realized. The channel spacing of the multiplexer is 0.8 nm and operating around the 1550 nm wavelength. Together the
developed material and process combine to produce AWG with an average insertion loss of 5 dB, the best channel shows
an insertion loss of 4.7 dB; the uniformity of 1 dB, a crosstalk of less than -28 dB and a polarization dependence loss
(PDL) of ~ 0.2 dB. During temperature cycling, a slight thickness hysteresis and refractive index hysteresis were
observed above the glass transition temperature and is ascribed to the fact that the terpolymer material may not
completely recover its elasticity in the heating/cooling cycle.
Properties of liquid inorganic-organic hybrid polymer optical waveguide materials
Show abstract
Two kinds of liquid photopatternable inorganic-organic hybrid polymer materials
polysiloxanes, named as PSQ-LL and PSQ-LH, are prepared by a sol-gel process at room
temperature. The refractive indexes of waveguide materials can be tuned linearly from 1.4482 to
1.5212 at 1310nm and from 1.4478 to 1.5198 at 1550nm by blending PSQ-LL and PSQ-LH. These
materials have low optical losses of 0.31dB/cm at 1310nm and 0.80dB/cm at 1550nm, and high
thermal stability with 1% decomposition temperatures of 297°C (in air) and 340°C (in N2) for
PSQ-LH and 313°C (in air) and 370°C (in N2) for PSQ-LL. Typical waveguide structures based on
PSQ-Ls are fabricated by UV imprint technology.
Crosstalk between two nonparallel waveguides in AWG demultiplexer
Show abstract
Based on the mutual coupling coefficient what derived from the method of field distribution analysis, the expressions of
coupling factor and coupling efficiency between two identical structure nonparallel straight rectangular waveguides are
suggested, and computing instances are introduced for showing the crosstalk between adjacent rectangular waveguides in
the star coupler of an AWG demultiplexer. Then, an approximation expression for computing the maximal crosstalk
between adjacent arrayed waveguides of an AWG demultiplexer is recommended. As the crosstalk between adjacent
arrayed waveguides of an AWG demultiplexer is in need of a limit, the expression for estimating the space between the
end face centers of adjacent arrayed waveguides in an AWG demultiplexer is advanced also, and a computing instance is
introduced for showing the crosstalk between adjacent arrayed waveguides in an AWG demultiplexer. Finally, based on
the Gaussian approximation for the mode field distribution of optical waveguide, the theoretical model of the spectral
response efficiency of an AWG demultiplexer is engaged, a computing instance is presented for showing the spectral
response characteristic and crosstalk characteristic of an bilateral symmetry structure AWG demultiplexer. These works
provides some help for ascertaining the basic parameters of an AWG demultiplexer.
All-optical wavelength conversions in PPLN waveguide with continuous and pulsed pumping
Show abstract
A theoretical model for description of the cSFG/DFG is developed in this paper. The factors influence the poled period of
PPLN is studied and the result shows that the poled period decreases while the temperature increases, and the poled
period also changes while we choose different signal wavelengths. In our simulation, a pulsed light is injected into a
PPLN waveguide as the signal, and then the performances of the wavelength conversion structures with two continuous
waves and two pulsed lights are compared in detail by numerical simulation. The output of these two situations are
educed while depletion, walk-off and nonlinear effect are all considered. The walk-off effects of output and conversion
efficiency are studied in both cases. The results demonstrate that there is an obvious walk-off between input signal and
output in the pulse pumped case, and in the CW case the converted wave width is boarder than that of input signal due to
pulse dispersion. Factors that influence the conversion efficiency are also analyzed including the power of the pump light,
the length of the PPLN waveguide and the experiment structure.
Photonic Crystal Fibers II
A design of large negative dispersion photonic crystal fibers
Show abstract
A fully vectorial effective index method and multiple-cladding method (FVEIM&MCM) is developed for modeling
photonic crystal fibers. Large negative dispersion photonic crystal fibers can be designed by changing the diameters of
the first, second and third ring of air-holes.
A linear step effective index model to study chromatic dispersion properties in high nonlinear photonic crystal fibers
Show abstract
By using the linear step effective index model (LSEIM), we analyze the chromatic dispersions (CDs) of high nonlinear
photonic crystal fibers (PCFs). The linear expression of the air filling fraction as a function of the relative air-hole size
is introduced for the cladding effective index. Then it is found that the LSEIM is an efficient method in high speed and
high precision. And this method demonstrated by experimental data can be widely used in not only larger relative air-hole
high nonlinear PCF, but also in the endlessly single mode PCF. Therefore, this research provides important
theoretical basis for the development and application of high-precision phase matching PCF.
Design of broadband dispersion-compensating microstructure fiber with large modal area
Show abstract
A broadband dispersion-compensating microstructure fiber is proposed. The designed fiber is shown to exhibit large
normal dispersion up to -2000ps/nm/km at 1550nm and compensate conventional single mode fiber within 0.6% residual
dispersion compensation ratio over a 100-nm wavelength range. Furthermore, the effective modal area is about 16μm2 at
1550nm.
Optical Buffer and Signal Processing
Potential optoelectronic devices for all-optical signal processing
Show abstract
We demonstrate three kinds of optoelectronic devices used to all-optical signal processing, namely, semiconductor
optical amplifier (SOA), periodically poled lithium niobate (PPLN), and microring resonator. Especially all these devices
are competitive for all-optical wavelength conversion, logic gates, and format conversion, etc.
SBS slow light using a novel optical fiber doped with nanoparticles
Show abstract
As the key of these all optical techniques which would be widely used in the future optical fiber communication, the
stimulated Brillouin scattering (SBS) slow light draws a great of attention and shows several advantages over other slow
light methods. With recent growth of nano-technology, researchers are hoping to improve the nonlinearity of the optical
fiber by using the nano-technology. According to this current situation, a numerical model of the SBS slow light and
three typical experiments are discussed. A novel optical fiber doped with nano material as InP is manufactured and
introduced into the SBS slow light, serving as the nonlinear medium of SBS process. And the numerical simulations are
performed to validate our method. The results show a considerable time delay of the optical light can be achieved
through this novel optical fiber.
A novel programmable all-optical buffer for optical packet switching network
Show abstract
In this paper, a novel all optical buffer based on cascaded double-loop all optical buffer (DLOB) unites is
proposed and demonstrated experimentally with the SNR analyze. This buffer is compact, simple, and inherently stable,
the delay can be adjusted in the range of 0 to 250us. By injecting a synchronizing control pulse, the operation of reading
and writing can be realized easily and the switch time is up to 20ps. The new optical buffer can be used in optical routers to
solve the packets contention.
Wavelength and power dependence of optical delay system utilizing HNLFs and DCF
Show abstract
Conversion wavelength and power dependence of the time delay and output signal quality for an optical delay
system consisting of dispersion compensation fiber (DCF) and highly nonlinear fibers (HNLFs) is investigated in
this paper. The numerical results show that the time delay generally varies linearly with the conversion wavelength
propagating through DCF and changes slightly with the power launched into HNLFs. But it has abrupt change at
some values of conversion wavelength or input power level. Output signal quality of the overall system varies
significantly with the conversion wavelength and input power level. The reasons behind these results are analyzed.
Finally, the input power level is optimized to achieve linearly varying time delay and desirable output signal
quality for an optical delay system.
Optical Fibers II
Optical coupling optimization for fiber lasers and devices
Show abstract
We review fundamental waveguide optics at a fiber joint between dissimilar specialty fibers and its diffusion
characteristics when the joint experiences thermal treatment. We then describe optical coupling techniques including
thermal diffusion and fiber tapering in order to achieve minimum transmission loss through the fiber joint. We discuss
the optical coupling property change due to diffusion and the effect of fiber taper ratio and taper length with application
examples.
Fabrication of specialty optical fibers using flash vaporization method
Borut Lenardic,
Miha Kveder,
Hervé Guillon,
et al.
Show abstract
Rare earth and metal ion doped optical fiber preforms have been produced using a novel flash vaporization method for
precursor delivery [1] into substrate tube. TEOS and solutions of organometallic compounds, containing lanthanide, Al,
Bi, Fe or Co were used. Use of TEOS and organometallic precursors makes this process similar to aerosol and sol-gel
processes, but glass is laid down in thin layers in MCVD fashion, strongly relying on thermophoretic forces. Preforms
with fully consolidated core layers have been made and were in most cases drawn to fibers. Results of these fibers and
preform glass composition are discussed.
Advanced multimode fiber for high-speed short-reach interconnect
Show abstract
In this paper, we describe the characteristics of advanced MMF, how it is specified, how it is manufactured, and update
its application in IEEE P802.3ba 40G/100G SR4/10 standards development.
Research on the fiber's UV transmission performance influenced by the doping process
Show abstract
With the increasing application in the ultraviolet (UV) area, the fiber's UV transmission performance should be studied.
In UV fibers, however, the presence of Germanium can result in ultraviolet radiation-induced color centers, which are
point defects in the core's silica that generate absorption bands in the UV and visible spectrum that deteriorate the optical
fiber transmission in that spectral region. The fiber's UV transmission performance would be influenced by the fiber
core's doping content. Based on the advanced plasma chemical vapour deposition process, three types of different
doping content fibers were fabricated. With test these fibers' transmission efficiency and stability, study the optimized
doping process of the UV fiber.
Silicon Photonics
Silicon nanophotonic waveguides and their applications
Show abstract
We discuss silicon photonic wires and components based on this technology, such as filters based on ring resonators,
interferometers or arrayed waveguide gratings. The devices are fabricated using standard CMOS technology,
including 193nm lithography. We also discuss their application in a number of demonstrator devices
within different application fields.
Applications of nonlinear effects in silicon wire waveguides: all-optical modulation, wavelength conversion, and quantum entanglement
Show abstract
We demonstrate efficient nonlinear functions using silicon nanophotonic structures. In the ultrasmall core of the
waveguides and cavities, nonlinear phenomena are significantly enhanced. Applying the two-photon absorption effect,
we have confirmed all optical modulation, in which the modulation speed is improved to around 50 ps by eliminating
free carriers. Applying the four-wave-mixing effect, we have achieved high-efficiency wavelength conversion. The
conversion efficiency is -11 dB, and the efficiency will be further improved by eliminating free carriers. Using the four-wave-
mixing effect, we have also realized a low-noise entangled photon pair source. The source does not need a
refrigeration system for noise reduction, which is a great advantage for practical application.
Nonlinear Signal Processing
A novel 80 km dispersion-compensation 8x100GHz comb-equalizer for fiber optical parametric amplifier
Show abstract
A novel dispersion-compensation superstructure fiber Bragg grating (SFBG) based comb gain equalizer for fiber optical
parametric amplifier (FOPA) is proposed. It is characterized by its eight-channel 100GHz DWDM-channel separations
and 80 km dispersion compensation function. The object reflectivity spectra of gain equalizer are calculated in two parts
independently. Inner channel part for every channel is designed according to the gain spectrum of fiber OPA. Inter-channel
part is calculated with Gaussian hypergeometric function (-0.5dB bandwidth 0.1nm, -45dB bandwidth 0.3nm) to
obtain slower rising and descending edges than the simply zeroed case. Then the SFBG is designed with layer-peeling
inverse scattering technique. Simulation results show that this SFBG satisfies all requirements. Using this SFBG as
comb gain equalizer, the gain of fiber OPA is flattened in every channel to within ±0.4dB among 8 ITU-T regulated
channels, with 80 km dispersion compensated.
Four-wave mixing-based all-optical signal processing with pulsed signal input
Show abstract
Four-wave mixing (FWM), including phase-insensitive amplification (PIA, no idler input) and phase-sensitive
amplification (PSA, with idler input), has been exploited for a wide range of applications in all-optical signal processing,
e.g. in-line amplification, wavelength conversion, optical-phase conjugation (OPC), amplitude limiter, phase
regeneration, etc. In a lot of those applications, the input signal is pulse. In this paper, the FWM-based signal processing
with pulsed signal input is analytically analyzed. A set of exact analytical expressions for the output amplitude and phase
is derived, taking into account the pump depletion and the self- and cross-phase modulation (SPM and XPM) from
pumps, signal and idler. For PIA, analytical analysis shows that the generated idler pulse is far away from the phase
conjugation of the input signal, and that the output signal is not an amplified replica of the input signal. These
phenomena are due to both the phase distortion caused by SPM/XPM from signal/idler, and the temporal envelope
broadening resulting from pump depletion. Besides, in the frequency domain, the spectral inversion between signal/idler
will be destroyed. The induced phase distortions of idler pulses in dual pumps case are found to be much smaller than
those of single pump case. For PSA, neglecting the SPM/XPM from signal pulse, chirp-free output signal pulse will be
obtained. However, the SPM/XPM from signal will cause frequency chirping to the output. For a pulse-sequence,
through the SPM/XPM, amplitude-fluctuation will cause phase-jitter thus destroy the phase regeneration. We found that
in some PSA configurations, the frequency chirping and phase-jitter mentioned above will be suppressed. Similar to PIA
case, the output signal pulse of PSA may be broadened due to pump depletion. In both PIA and PSA applications, the
implications of the phase and shape distortions in all-optical signal processing by FWM are discussed.
Fiber stimulated Brillouin scattering-based microwave signal processing
Show abstract
Microwave signal generation and processing such as frequency conversion are proposed and experimentally
demonstrated based on stimulated Brillouin scattering (SBS) in single-mode fibers (SMFs). A simple scheme to generate
microwave/millimeter-wave sources is realized by utilizing the optical heterodyne technique between an optical carrier
and its Stokes light. Stable microwave sources with the frequencies of about 10.56 and 21.71 GHz are experimentally
realized using the first- and second-order SBS frequency shifts based on standard SMFs. A microwave frequency
up/down conversion method is presented without premodulation for bi-direction radio-over-fiber systems by using fiber
SBS. The microwave signal of 1.5 GHz is experimentally up-converted to 9.06 and 12.06 GHz, and the microwave
signal of 9 GHz is down-converted to 1.56 GHz, respectively.
Investigation of nonlinear optical loop mirror based optical thresholding for high speed OCDM system
Show abstract
The nonlinear optical loop mirror (NOLM) and the nonlinear amplifying loop mirror (NALM) based optical
thresholding in the high speed OCDM system are analyzed, the input pulse peak power of the NOLM is
optimized considering the thresholding decision function, pulse shaping and side-lobe suppressing of the NOLM
based on high nonlinear fiber (HNLF) are numerically simulated, and theoretical investigation is compared with
experimental result. The results show that the interference noise in the 40 Gbit/s OCDM system could be
suppressed effectively by the optical thresholding techniques based on the NOLM and the NALM. We show that
the NOLM and the NALM can act as a nonlinear processing element capable of reducing both the pedestal
associated with conventional matched filtering and the width of the associated code recognition pulse.
Optical Switches
High-speed switching of a DFB grating in a twin-hole fibre
Show abstract
A distributed-feedback (DFB) grating was written in twin-hole fibres with internal electrodes. Due to the intrinsic
birefringence, the grating has two ultra-narrow peaks (~0.41 pm and ~0.27 pm) corresponding to x- and y-polarization.
The separation between them can vary from 40 pm to 104 pm when the temperature increases from room temperature to
96°C. The dominant contributions of the Bragg wavelength shift as the increasing temperature are the change in
refracitive index of the fibre and the expansion of the substrate (largest). Under the current pulses excitation, full on-off
switching with response time ~2.5 ns has been achieved for x-polarization of the DFB grating.
Research on 1x2 all fiber high-speed magneto-optic switch
Show abstract
In this paper two new types of 1x2 all fiber high-speed magneto-optic switches with thick film ferromagnetic bismuth-substituted
rare-earth iron garnets are proposed and tested. Two types of magneto-optic switches are discussed by using
two kinds of crystals. One is the ordinary switch which needs indurance magnetic field to maintain its state; And the
other is latching type switch, the crystal remains in a given magnetic state for unlimited duration without energy supply.
Circuits used to generate magnetic field are also discussed. The theoretical and experimental analysis of optical route,
measurement of switching time and magnetic filed etc. are included. The extinction ratio of the switches are currently
about 20 dB. It can be improved further by additional Faraday rotation created by another magneto-optic (MO) material
in the light path. The switching time of MO material is under 100 ns, it can be ignored. Magnetic field should be able to
change the voltage rapidly in order to obtain fast operating time of the optical switch. The inductance of the solenoid
used for generating the required magnetic field is the bottleneck for rapid switching of the magnetic field in the MO
material. The switching time of the two optical switch are discussed.
Analysis and design for ultrafast magneto-optic switch
Show abstract
In the paper, a high speed magneto-optic switch based on the Faraday Effect is designed and analyzed. The novel
magneto-optic switch presented in this paper will satisfy high speed transmission and exchange of optical-message
through all-optic network. It consists of three important components as followed novel optical route, Faraday rotator
configuration with ultrafast magnetic field and picosecond impulser. It may switch the optical route by controlling
Faraday rotator which is supplied by picosecond impulser. By the development of the magneto-optic crystal, and
ultrafast magnetic field, the designed magneto-optic switch featured as low insertion loss, low crosstalk, high switching
speed and small bulky size gets ahead of traditional optic switches. As the first part of this paper, a design scheme of
optical route in high speed magneto-optic switch and its experiment analysis will be discussed. Good avalanche effect of
transistor FMMT415 is adopted to generate picosecond pulse signal and then to drive the high speed magnetic field.
Shown by the experiment data, the rising time of the impulse about 1ns, the amplitude of the impulse about 100~500V
are available on the Output end from the picosecond impulser, which can be used as driving current pulse of Faraday
rotator. By using the relationship between the polarization plane rotate direction of polarization light and magnetic
direction, the Faraday rotator is designed.
Electro-optic polymer assisted optical switch based on silicon slot structure
Show abstract
One kind of electro-optic polymer assisted Mach-Zehnder optical switch based on silicon slot structure is presented. By
filling electro-optic material in the void slot of the arms, direct electro-optic modulation can be introduced. Theoretical
model and detailed analysis is given in this paper.
Ring-resonator-assisted optical switch with high extinction ratio
Show abstract
This paper presents a novel micro-ring-resonator-assisted structure as an optical switch. This device couples two outputs
of a 1x2 power splitter into a micro-ring resonator (MRR). The double-beam interference will occur in the MRR. If the
phase difference between the beams and the coupling coefficients of MRR are set properly, the device can switch the
light by applying phase shift on MRR. High extinction ratio or low crosstalk can be achieved, even if the modulation
additional loss is large.
Polarization Effects
Wide band single polarization and polarization maintaining fibers with stress rods and air holes
Show abstract
We present a novel fiber design using both stress rods and air holes for making wide band single polarization fibers as
well as polarization maintaining fibers. The key factor that makes the fiber design possible is that the stress-induced
birefringence from the stress rods and the form birefringence from air holes are added constructively, which increases
the total birefringence and allows more flexible choice of fiber parameters. We established a finite element model that is
capable to study both the stress-optic effect and the wave-guide effect. Through the detailed modeling, we
systematically explore the role of each major parameter. Different aspects of the fiber properties related to the
fundamental mode cutoff, fiber birefringence and effective area are revealed. As a result, fibers with very large single
polarization bandwidth as well as larger effective area are identified.
Study on the performance of the stress area mismatched Panda erbium-doped polarization-maintaining fiber
Show abstract
Influence of stress area mismatched Panda erbium-doped polarization-maintaining fibre on the birefringence is analyzed
and compared by finite element method and approximate analytical expression educed by the complex variable method
of elasticity with superposition techniques.
The least DOFs required for a polarization controller in PMD compensator
Show abstract
Automatically controlled polarization controllers (PC) are the essential integral parts in an automatic compensator for
polarization mode dispersion (PMD). It is suggested by Prof. M. Karsson et al. at Charlmers University of Technology,
and afterward widely accepted that we need to adjust only two waveplate PC (two degrees of freedom, DOF) for each
stage PMD compensator to complete PMD compensation. It is equivalent to say that only two of degrees of freedom for
each PC are needed to complete the state of polarization (SOP) transformation from any input state into any other state
covering the entire Poincare Sphere. In this paper will take two types of commercial available PC as examples to prove
theoretically and experimentally that except for the reset-free problem it is necessary to adjust at least three instead of
two waveplates in order to transform any input state into any other state covering the entire Poincare Sphere. Therefore
we can achieve complete PMD compensation at least using 3 DOF instead 2 PC in each stage PMD compensator.
Investigation of cross-polarization modulation in semiconductor optical amplifier
Show abstract
A matrix theory which is capable of describing the Cross-polarization modulation (XPolM) in semiconductor optical
amplifier (SOA) is presented in this paper. Using the transfer matrix method, we prove that there exists Principal State of
Polarization (PSP) vector and Polarization Dependent Gain (PDG) vector in SOA. The evolution of output SOP on the
Poincare Sphere (PS) can be decomposed into two circles, which are induced by PDG and Polarization Dependent Phase
Shift (PDPS), respectively. The expressions of PSP vector and PDG vector with regard to inner parameters of SOA are
obtained. The pump-power induced evolution of output SOP is investigated experimentally. The experimental results
accord well with this matrix theory.
Polarization-induced phase noise in fiber optic Michelson interferometer with Faraday rotator mirrors
Show abstract
Polarization-induced phase noise in Michelson interferometer with imperfect Faraday rotator mirrors was investigated.
This kind of noise generates from the rotation angle errors of Faraday rotator mirrors and external polarization
perturbation. The conversion factor κ, representing the magnitude conversion ability from polarization-noise to
polarization induced phase-noise, have been theoretically evaluated and experimentally investigated.
Fiber Sensors
Temperature insensitive strain sensors based on high birefringence fiber loop mirror with a single fiber Bragg grating
Show abstract
In this letter, a novel optical sensor based on high birefringence fiber loop mirror with a
single Fiber Bragg Grating, available for temperature insensitive measurement for strain, was
proposed and demonstrated. Considering that the HBFLM (high birefringence fiber loop mirror)
and the conditional Fiber Bragg Grating have different response to strain and temperature,
respectively, we can detect both the peak wavelength shift of these two devices. So we can build a
lineal matrix equation between the perturbation of the surrounding and the shift of the
transmission spectrum. Compared with conditional sensors for simultaneous measurement, this
kind of sensor has several advantages, including simple configuration, low cost and easy to be
fabricated.
Raman-based distributed temperature sensor using a 1.66um ring type Q-switched fiber laser with adjustable pulsewidth
Show abstract
An optimized 1.66μm Q-switched fiber laser is demonstrated for Raman-based distributed temperature sensor. In a ring
type Q-switched erbium-doped fiber laser, 850m TrueWave fiber is introduced to serve as both delay line fiber and
Raman gain medium so that in addition to the wavelength shifted to 1.6μm, the pulse duration and the buildup time can
be relatively extended. By properly controlling the fall edge of the acousto-optic switch, the pulse duration of 30-74ns
with peak power of 1.3-3.3W is achieved. Based on this light source, a 2.4km Raman-based distributed temperature
sensor is obtained with temperature resolution of 1°C and spatial resolution of 8m.
The research of multi-parameter sensor based on two-mode highly birefringent photonic crystal fibers
Show abstract
Two-mode highly birefringent optical fibers support two spatial modes. The two spatial modes can be used to set up two
detectors. The birefringence would change with the variety of environment. Therefore, two-mode highly birefringent
optical fibers can sense two parameters synchronously. A finite element method (FEM) was used to numerically
calculate the distribution of pressure, distribution of temperature and the birefringence variety versus pressure and
temperature in two-mode highly birefringent photonic crystal fibers. Based on the single parameter sensor, the
muti-parameter sensor was analyzed. The results show that the muti-parameter sensor can measure pressure and
temperature synchronously.
Investigations of a novel mechanical anti-aliasing filtering fiber-optic hydrophone with a cylindrical Helmholtz resonator
Show abstract
In general, an operational sonar system will require an anti-aliasing low-pass filter if any high frequency components are
present in the sensor phase information. A mechanical filter must be used in the sensor since anti-aliasing filtering must
be performed before sampling. Fiber-optic hydrophones with mechanical anti-aliasing filter, which consists of soft
closed-cell sponge rubber, have been reported, but they have poor ability of resistance to hydrostatic pressure due to the
softness of the rubber. Furthermore, the theoretical analysis and design of the hydrophone are difficult due to the
uncertainty of the rubber's mechanical properties. To effectively eliminate the aliasing in a practical sonar system based
on interferometric fiber-optic hydrophones, a novel mechanical anti-aliasing filtering fiber-optic hydrophone with a
cylindrical Helmholtz resonator has been proposed. The low frequency lumped parameters model of the fiber-optic
hydrophone is given based on the theories of electro-acoustic analogy, and the acoustic properties are analyzed using the
standard circuit analysis methods. The acoustic sensitivity frequency response is measured in a standing-wave tube using
a comparative measurement method. Experimental results show that this new type of fiber-optic hydrophones has good
acoustic low-pass filtering performance. The low frequency response, as determined by the sensing mandrel and the fiber
optical interferometer, is very flat and the average acoustic phase sensitivity is about -140 dB re 1rad/μPa with a
fluctuation within ±1.0 dB. The response curve has a resonant frequency determined by the hydrophone structure. Apart
from the resonant frequencies and the high frequency responses, the measured response curves are well in agreement
with the simulation results, which show the correction of the model and the theories. It is expected that this new type of
mechanical anti-aliasing fiber-optic hydrophone will have wide potential applications in modern sonar systems.
Analysis of a new measurement for electromagnetic with fiber grating
Show abstract
A New magnetic field measurement based on polarization effect of fiber grating was analyzed in theory and
experiment. The simulations show the linear relationship between the peak value of PDL and magnetic field in
certain range. Moreover, this method is temperature insensitive. The precision of this method is 2Gs using the
optical vector analyzer in experiment and agree well with the theory.
Temperature dependence of the strain response of chemical composition gratings in optical fibers
Show abstract
Chemical composition gratings, used as strain sensing elements at high temperature environments, show a temperature
dependence of their strain response. Temperature dependence of the strain response of CCGs over a range of
temperatures from 24°C to 900°C has been measured. It is found that the wavelength shift of CCGs is linear with applied
tensile strain at a constant temperature, and the strain sensitivity is 0.0011nm/με.
Fiber Lasers
Fiber fuse in high-power optical fiber
Show abstract
This paper describes the observation of a fiber fuse observed in the core of a high-power high-NA, all-glass, double-clad fiber. Fiber fuse is a phenomenon that results in a specific type of
catastrophic destruction of an optical fiber-core from the point of initiation toward the light
source. It is so named because its appearance is very similar to a burning fuse. In this paper, we
examine the origin or the initiation source for the fiber fuse observed in the double-clad fiber.
Furthermore, we propose a two-step thermal mechanism for the fiber-fuse generation in optical
fiber.
Experimental investigation of double-clad Tm3+-doped silica fiber amplifying at 1.99um
Show abstract
The LD-clad-pumped CW and Q-switched pulse Tm3+-doped silica fiber amplifiers were general experimental
investigations. The CW fiber amplifier provided up to 3W output with the slope efficiency nearly 30%, and the Q-switched
pulse fiber amplifier output power was 2W with the slope efficiency 32.6%. The gain fiber was 27.5/400μm D-shaped
Tm3+-doped silica double-cladding fiber, and the pump sources was a 792nm LD with a 400μm pigtail fiber
output. The signal seed sources was a LD-pumped Tm3+:YAP lasing at 1.99μm. By the AO Q-switched method, The
Tm3+:YAP laser had a nearly 120ns pulse duration and 1kHz repeat rates. The measured amplified spectrum only
stretched a little relative to the input signal spectrum.
High-power narrow-linewidth wavelength-tunable YB3+-doped double-clad fiber lasers
Show abstract
Based on an external cavity using Littrow configuration, a high-power, narrow-linewidth and broadband-tunable Yb3+-doped double-clad fiber (YDCF) laser was demonstrated. Numerical simulations were performed to optimize the design
of the laser. A wide wavelength tuning range from 1046 nm to 1121 nm was achieved. The 3-dB linewidth of the laser
was up to 0.5 nm. An output power of over 20W at 1089 nm with a slope efficiency of 60% was achieved.
Optical Devices
Transmission enhancement of a metallic slit by a nearby metallic nano-particle
Show abstract
We propose to use a nearby metallic nano-particle to greatly enhance the transmission efficiency of a nano-slit aperture
in a metallic film. The metallic nano-particle helps to form a T shape cavity which could effectively transform the
propagating incident light into localized near-filed light. Harvest efficiency is enhanced by 20 times for a non-resonant
25 nm-width nano-slit.
High-speed optical hold module in optical assisted ADC
Show abstract
High-speed Photonic Analog-to-Digital Convertor (ADC) has attracted intense interest of researchers for the past three
decades, for it has the potential applications in areas that have extreme bandwidth requirements, such as radio astronomy,
real-time measurements and so on. Photonic ADCs can be categorized into two major classes: optical assisted ADC and
all-optical ADC. In optical assisted ADC, the sampling is performed in optical domain and the quantization is done in
electrical domain. In all-optical ADC, the sampling, quantization and coding are done in optical domain. Optical assisted
ADC combines the ultra-stable, ultra-low time jitter characterizations of mode-locked lasers and mature high-speed
electronic circuits, therefore it is much easier to implement in practical systems. However, the ultra-short (less than tens
of pico-seconds) post-sampling pulse sequence required by high resolution ADC places a challenge for the following
electrical processing, because ultra-high-speed (>2GHz) "integrate-hold" circuits are hard to design and manufacture. In
this paper, an optical hold module (OHM) is proposed, theoretically analyzed, numerically simulated and experimentally
demonstrated, which can be used to replace ultra-high-speed "integrate-hold" circuits and has more merits than the latter.
This optical hold module has potential applications in several other areas, such as fiber sensors, and so on.
All-optical correlator based on 3x3 coupler with feedback for optical header processing
Show abstract
A novel correlator based on 3x3 coupler with dual loops which perform XOR operation and feedback
with power compensating is proposed. The validity of device is demonstrated by the simulation with realistic parameters
at 10Gb/s and 40Gb/s. For this kind of correlator, the amplified spontaneous emission (ASE) noise accumulation is the
crucial limitation. The relationship between the output signal-to-noise ratio (SNR) and bits to be compared is analyzed
theoretically. The ASE noise is retrained and the output SNR is enhanced by introducing the assistant light advisably.
Therefore, this device can perform the comparison of arbitrary length data. If the dual loops length is minimized by
integrate, the devise is applicable for the higher speed data.
All-optical flip-flop based on the optical bistable Fabry-Perot laser diode with fiber-Bragg-grating external cavity
Show abstract
We demonstrate a novel optical flip-flop configuration which consists of one Fabry-Perot laser diode
(FP-LD) and two Fiber-Bragg-Gratings (FBG).The all-optical flip-flop is realized based on the optical bistability of
injection-locked single-mode of FP-LD. The essential part to obtain bistability in this system is that the output of FP-LD
is fed back partly by two FBGs at certain wavelengths. The EDFA was used to adjust the power of feedback beam. The
on or off state of the All-optical flip-flop is determined by the set or reset light externally at different wavelength. The
all-optical flip-flop operated at the wavelength of 1537nm with on-off contrast ratio of 15 dB. The theory and
experimental result are presented.
Broadband optical directional full couplers based on Blackman function
Show abstract
A mismatched optical coupler with waveguide weighted by the Blackman function is numerically
investigated in the demand of short-length, C+L-band, low crosstalk, and process tolerance. Utilizing the full
factorial design, the structure parameters of coupling waveguide are obtained by beam propagation method. In
the condition of crosstalk of -33.5 dB, the mismatched optical coupler with proper selected waveguide structure
parameters is found to have a coupling length of 2.80 mm in the transmission wavelength ranges of C+L-band
(1.53~1.61 μm). Obviously, the selection and design of waveguide structure are very important to satisfy the
qualities of a mismatched optical coupler for the demand of short-length, bandwidth, and low-crosstalk.
Microstructured Fibers
Finite element analysis of propagation characteristics for an Octagonal Photonic Crystal Fiber (O-PCF)
Show abstract
An octagonal photonic crystal fiber (O-PCF) structure with eight air-holes on the first ring is proposed based on a unit
isosceles triangle. The mode effective index and chromatic dispersion of the O-PCF are numerically investigated by
employing the finite element method. It is found that under the same value of air filling fraction (AFF), the octagonal
photonic crystal fiber has smaller mode effective index and higher amplitude of dispersion. On the other hand, the
dispersion of O-PCF can be easily controlled through adjusting appropriately the air-hole pitches and air-hole diameters.
Single-mode TE01 fibers
Show abstract
We show that, using index guidance within an isotropic all SiO2 structure of only 4 layers, it possible to design an optical
fiber that supports just one mode of a single polarization: the azimuthally polarized TE01 mode. In particular a ring guide
of appropriate index of doped SiO2, thickness and radius guides TE01 as the fundamental mode. Then an outer layer can be used to cut off higher order modes. This design is in contrast to those that require Bragg guidance or anisotropic
materials.
Fiber Ring Lasers
Optical injection mode-locking and DWDM channeling of the weak-resonant-cavity FPLD-based fiber ring lasers
Guo-Hsuan Peng,
Yu-Chan Lin,
Kuen-Cherng Lin,
et al.
Show abstract
10-GHz optical injection mode-locking of a weak-resonant-cavity Fabry-Perot laser diode (WRC-FPLD)
with 10%-end-facet reflectivity based fiber ring with an intra-cavity power controlled wavelength shift and a reducing
chirp linewidth at high intra-cavity coupling ratio condition is demonstrated. Both the strong dark-optical comb and
strong feedback coupling contribute to the red shift of mode-locking spectrum. The wavelength shift from 1536 to
1542 nm of the WRC-FPLD based fiber ring associated with its pulsewidth and linewidth also reduced from 27 to 19
ps and from 10 to 6 nm, respectively, can be observed. The peak-to-peak frequency chirp reduced from 3.5 to 1.8 GHz
was caused by the shrink of linewidth. The WRC-FPLD exhibits relatively weak cavity modes and a gain profile
covering > 33.5 nm. The least common multiple of the WRC-FPLD and the fiber-ring mode-spacing is tunable by
adjusting length of the fiber ring cavity to approach intracavity mode spacing of 1.6 nm. Up to 12 lasing modes
naturally and a mode-locking pulsewidth up to 19 ps can be observed. With an additional intracavity bandpass filter,
the operating wavelength can further extend from 1520 to 1553.5 nm. After channel filtering and linear dispersion
compensating, the pulsewidth can be further compressed to 8 ps with corresponding chirp reducing from 9.7 to 4.3
GHz. Such a mode-spacing tunable pulsed fiber laser matching ITU-T DWDM channels can be employed as a novel
optical carrier to integrate the OTDM function into the DWDM system with a channel spacing tunable from 50 to 200
GHz.
Multiwavelength emission and passive mode-locking from a same fiber laser with nonlinear optical loop mirror
Show abstract
Fiber laser with two polarization-dependent output states is demonstrated.
On one hand, nonlinear polarization rotation induced intensity-dependent loss of
nonlinear optical loop mirror can balance mode competition of homogenous
broadening gain medium, and thus allows for stable room-temperature
multiwavelength generation. On the other hand, intensity-dependent transmission can
act as an equivalent saturable absorber, which results in passively mode-locking of
fiber laser. It may be a potential multifunction fiber laser.
Tunable single polarization Yb3+-doped fiber ring laser by using intracavity tilted fiber Bragg grating
Show abstract
A tunable single polarization Yb3+-doped fiber laser using 45° tilted fiber Bragg grating is demonstrated. It generates
high degree of polarization (>99.86%) 1.06μm laser with 25 nm wavelength tuning range. This 45° tilted fiber Bragg
grating was fabricated using a zero-order-nulled phase mask. It has a near constant polarization-dependent loss (PDL)
across a wide wavelength range (1030 to 1080 nm).
Discretely tunable narrow linewidth fiber ring laser based on matching the transmission spectra of two fiber Bragg grating Fabry-Perot filters
Show abstract
A novel narrow linewidth, discretely tunable and stable fiber ring laser based on the matching of the transmission spectra
of two fiber Bragg grating Fabry-Perot (FBG-FP) filters is proposed in this paper. We studied the characteristics of this
sort of tunable fiber laser both theoretically and experimentally, and obtained eight discretely tunable lasing wavelengths
from 1552.24 nm to 1552.912 nm with an average 96 pm spacing, by pulling one of the FBG-FPs. The output of the
laser at the discrete wavelengths specified by the transmission maximum of the fixed FBG-FP is quite stable, and the
fluctuation of the output power is less than 0.1dB.
Characteristics of active mode-locked fiber ring laser based on semiconductor optical amplifier
Show abstract
An active mode-locked fiber ring laser based on XGM in SOAs is demonstrated with an external pulse sequence. The
laser operates at a variable repetition rate from 1GHz to 15GHz, even up to 40GHz with an additional fiber-based
multiplexer. By a wavelength tunable filter, a wide wavelength tunable span about 37nm is achieved continuously
between 1528nm to 1565nm. Without any pulse compression device, the pulse sequence with low pulsewidth about 12ps
and high output power about 9dBm can be obtained in different operation repetition rate. The output pulses show a time
jitter low than 180fs in all operation repetition rate. A detailed analysis is done experimentally to investigate the
relationship between parameters of the SOA-based fiber ring laser and pulsewidth of the generated mode-locked pulses.
Discretely tunable SOA-fiber laser based on few-mode polarization maintaining fiber in Sagnac interferometer
Show abstract
A discretely tunable fiber ring laser based on a Sagnac interferometer incorporating a few-mode polarization maintaining
fiber and semiconductor optical amplifier as the gain media is presented. Nine lasing wavelengths at a tuning step of 2.5
nm is achieved with side-mode suppression ratio over 20 dB.
Optical Filters
Widely tunable Gaussian-shaped spectral filters using dispersion-engineered fibers for bioimaging applications
Show abstract
Optical liquids can be used to engineer the dispersion characteristics of fibers by serving as
the core or cladding. The short-/long-pass filters are so made and concatenated to achieve
widely tunable Gaussian-shaped filters for bio-imaging.
How to design an easily deposited multi-band-pass filter
Show abstract
A systemic design on multi-bandpass filters is developed based on a plurality of Fabry-Perot(FP) interferometers, which
are composed of a cavity between mirrors. Certain number of passbands can be built by selecting the number of cavities,
while the band-width and the band- interval can be adjusted by the total layers contained in mirrors. By changing the
configuration of mirrors and cavities a huge group of multi-band-pass filter will be developed. Among many multi-bandpass
filters given here several of them are tested. A double-passband filter is deposited on a super-thin substrate of
thickness about 5 μm. One of its passbands situates 1550nm, three rejection bands situate 1310nm, 1490nm and 1640nm
make this filter very useful for B-PON and GE-PON in the fiber communications. A triple-bandpass filter with four
rejected bands is deposited on glass, its high transmittance in passbands and high isolation in rejection band make it a
valuable filter for Add/Drop device. In another deposition its three passbands can transmit blue, green and red (B, G and
R) lights but reject other lights which otherwise become noise to the B, G and R light signals. The good performances of
the filters deposited above prove that multi-bandpass filter designed by this way is easy to do.
Ultra narrow flat-top filter based on multiple equivalent phase shifts
Show abstract
Instead of real phase shifts, equivalent phase shifts (EPS) are adopted to construct ultra narrow phase-shifted band-pass
filer in sampled Bragg gratings (SBG). Two optimized distributions of multiple equivalent phase shifts, using 2 and 5
EPSs respectively, are given in this paper to realize flat-top and ripple-free transmission characteristics simultaneously.
Also two demonstrations with 5 EPSs both on hydrogen-loaded and photosensitive fibers are presented and their
spectrums are examined by an optical vector analyzer (OVA). Given only ordinary phase mask and sub-micrometer
precision control, ultra-narrowband flat-top filters with expected performance can be achieved flexibly and cost-effectively.
All fiber tunable band-pass filter based on dual acousto-optic mode coupling
Show abstract
We propose an all fiber tunable band pass filter based on dual acousto-optic mode coupling scheme. By applying two
acoustic waves on a piece of etched single mode fiber, the feasibility of the filter is demonstrated experimentally. The
tunable characteristics of the device are discussed theoretically.
Fiber Gratings
Transfer matrix model of the fiber grating external cavity semiconductor laser
Show abstract
Based on the coupled mode theory, the transfer matrix approach is presented to investigate the fiber grating external
cavity semiconductor lasers (FGECSL). As a result, the P-I curve, the lasing wavelength and the side-mode-suppression-ratio
(SMSR) have been investigated numerically in detail. With the length of the fiber grating increasing, the reflection
spectrum of FGECSL changes obviously, the threshold current and threshold carrier density decreases, the mode
distribution is irregular, and the output spectrum becomes complex. Moreover, the optical bistablility is also observed.
Wavelength-spacing-tunable multiwavelength filter and laser using a fiber grating-based distributed F-P interferometer
Show abstract
Wavelength-spacing-tunable multiwavelength filters and lasers have been realized using a superimposed chirped-fiber
Bragg grating based distributed Fabry-Perot interferometer incorporating with a beam-bending chirp tuning method.
Continuously wavelength spacing tuning of 0.3-0.6 nm has been achieved.
Recent development on CO2-laser written long-period fiber gratings
Show abstract
The paper reviews the recent progress on CO2-laser writing of long-period fiber gratings (LPFGs) in different kinds of
fibers, including conventional single-mode fiber (SMF), boron-doped SMF, polarization-maintaining fiber, photonic
crystal fiber, and polarization-maintaining photonic crystal fiber. In particular, we report the writing dynamics for the
understanding of the physical mechanisms involved in the writing process and show that the CO2-laser pulses can not
only relax the internal stress in the fiber core but also induce a frozen-in stress in the cladding of the fiber under tension.
The applications of CO2-laser written LPFGs, especially for the realization of broadband optical couplers, are also
discussed.
Optical resonance analysis of reflected long period fiber gratings with metal film overlay
Show abstract
We present the experimental results of a novel single-ended reflecting surface plasma resonance (SPR) based long period
fiber grating (LPFG) sensor. A long period fiber grating sensing device is properly designed and fabricated with a pulsed
CO2 laser writing system. Different nm-thick thin metal films are deposited on the fiber cladding and the fiber end facet
for the excitation of surface plasma waves (SPWs) and the reflection of the transmission spectrum of the LPFG with
doubled interaction between metal-dielectric interfaces of the fiber to enhance the SPW of the all-fiber SPR-LPFG
sensing system. Different thin metal films with different thicknesses are investigated. The effect of the excited SPW
transmission along the fiber cladding-metal interface with silver and aluminum films is observed. It is found that
different thicknesses of the metal overlay show different resonant behaviors in terms of resonance peak situation,
bandwidth and energy loss. Within a certain range, thinner metal film shows narrower bandwidth and deeper peak loss.
High sensitive pulse measurements using nonuniform quasi-phase matching gratings
Show abstract
Some experiments of optical performance monitoring (OPM) with uniform or nonuniform
quasi-phase matching (QPM) gratings waveguides have already been demonstrated during the last few
years. Theoretical analyses based on coupled-wave equations are carried out for nonuniform QPM
gratings. The generation process of SHG in nonuniform QPM gratings is simulated and the outcome
comparison between uniform and nonuniform QPM gratings, which demonstrate that nonuniform QPM
gratings are more suitable for the OPM systems, is carried out in this paper. The value of grating chirp
coefficient of the chirped PPLN has influence on the efficiency and band width of the output pulse. The
relation between them is also discussed. These are new simulative attemptation to apply the
nonuniform quasi-phase matching gratings into optical performance monitoring system.
Nonlinear Effects
The study of the gain characteristics of 1.66um fiber Raman amplifier with ordinary single-mode fiber
Show abstract
We constructed a fiber Raman amplifier with an ordinary single-mode fiber in the U-band located on the 1.66μm for the
first time. This paper studies the gain characteristics of FRA by using the pump sources with different property and
different power. Experiments showed the system amplified steadily when pump power was tens of milliwatt. To the
same pump sources, as pump power is increased, the gain of the signal improves obviously. In the case of identical pump
powers, FRA' gain is also concerns with the pump source's type and the pump way. When the double-clad Er-Yb codoped
fiber laser was used as the pump source, though our 1.66μm fiber Raman amplifier, the signal was amplified
effectively and the maximal peak gain reached 5.11dB.
Demonstration of a multiwavelength laser source based on supercontinuum generation in dispersion-flattened holey fiber
Show abstract
A spectral sliced multiwavelength laser source which utilizes supercontinuum generated in a high nonlinear dispersion
flattened holey fiber(HNL-DF-HF) and spectral slicing in an arrayed waveguide grating has been demonstrated. All 32
channels exhibit almost constant pulsewidth, the channel separation is 100GHz, and crosstalk of the adjacent channels is
more than 25dB.
Modulational instability in highly nonlinear media
A. B. Moubissi,
Th. B. Ekogo,
S. B. Yamgoue,
et al.
Show abstract
We consider the continuous wave propagation in a highly dispersive and nonlinear medium wherein the wave
propagation is governed by the generalized nonlinear Schrodinger equation. We demonstrate the novel flat-top
modulational instability gain for a wide range of modulation frequencies in the anomalous dispersion regime of highly
dispersive and nonlinear media. We find that the resulting MI gain is independent of input power. Besides, we compare
the analytical results with those of numerical results.
All-optical low-pass filter based on cross-gain modulation in fiber optical parametric amplifier
Show abstract
An all-optical low-pass filter utilizing cross-gain modulation (XGM) in fiber optical parametric
amplifier (OPA) has been proposed and experimentally demonstrated. In this proposed low-pass filter,
the pump, signal and a continuous-wave probe were launched in the highly-nonlinear fiber (HNLF) to
introduce OPA and thereby XGM effects. Pump, signals and idlers were then being separated and then
filtered. With suitable time delay being introduced into different optical paths, the low-pass filter was
implemented, which was verified with the experimental results of pseudo-random signal. The timing
waveforms of the filtered signal were shown, followed by the transfer function of the low-pass filter's
frequency response. They all showed a good agreement with the numerical results.
Poster Session
Hole-assisted lightguide fiber for dispersion tailoring
Show abstract
The exploitations of air holes in optical fiber design have been receiving growing research interest since the first
photonic crystal fiber (PCF) was demonstrated. Many peculiar optical properties are achievable with the flexible control
of the geometry of the air holes in the microstructured cladding. Different from the complex geometry of microstructured
cladding in the holey PCF, hole-assisted lightguide fiber (HALF) is based on conventional optical fiber design and
therefore guides light by total internal reflection. The existence of the assisting air holes in the cladding helps to tailor the
optical properties of the fiber. In this work, the dispersion tailoring is demonstrated by varying the structural parameters
and material properties of the fiber. Additional tunability is achieved by infiltrating substance with tunable refractive
index into the assisting holes.
All-optical clock recovery CSRZ-format data at 40Gbit/s using SOA-based ring laser
Show abstract
The paper firstly demonstrates a theoretical investigation of clock recovery from carrier-suppressed return-to-zero
(CSRZ) modulation format data at 40Gbit/s by using SOA-based ring laser. And a completely numerical analysis about
the clock characteristics at 40Gbit/s is done, which is an effective guide for experiment and necessary to optimize the
system performance. Meanwhile, simulation results show high-quality clock recovery from 27-1 PRBS CSRZ data at
40Gbit/s can be achieved by using higher power assist CW light into a SOA-based ring laser.
A novel ultrafast all-optical NRZ to RZ format converter based on Sagnac interferometric structure
Show abstract
A simple novel ultrafast scheme of all-optical nonreturn-to-zero(NRZ) to return-to-zero(RZ) is proposed based on
Sagnac interferometric structure. The operations of this scheme at 40Gbit/s 27-1 PRBS sequences are simulated correctly
with the output extinction ratio more than 19.1dB. Through built theoretical model and numerical analysis, the operating
characteristics of the scheme are illustrated. Furthermore, the carrier recovery time of the SOA is no more a crucial
parameter to restrict the operation speed of this scheme.
Photoluminescence of copper ion-exchanged planar waveguides in commercial soda-lime glass
Show abstract
Copper-doped planar glass waveguides were prepared by the thermal ion-exchanged of commercial soda-lime glass
wafers in molten mixture of CuSO4 with sodium sulfates at temperature of about 600°C. The effective indices were
measured by means of prism-coupled technique, and the guided modes were not monotonic increasing with the ionexchange
times. The properties of photoluminescence (PL) spectra of the waveguides were studied. The broad emission
bands centered at around 520 nm (at the excitation wavelength of 310 nm, at the room temperature) were measured on
the samples, which were also strongly influenced by the ion-exchange times and the intensity of the PL emission is not
monotonic increasing with the ion-exchange times as well.
Design of tunable wavelength selector with fiber Bragg gratings with cladding made of Electro-optic materials
Show abstract
A new tunable wavelength selector based on the fiber Bragg grating with cladding made of LiNbO3 with optical axis
running along the axis of fiber Bragg grating was investigated. The calculated results indicate that the reflected
wavelength can be tunable from 1550.921 nm to 1548.9668 nm with variation of electric field running along the fiber
axis from 107 to 108V/m, the reflectivity varies from 99.8252% to 99.9715%. The tunable wavelength range will be large
with the electric field increases. These rules indicate that the new tunable wavelength selector based on the fiber Bragg
grating with cladding which is made of uniaxial anisotropic electro-optic crystal material can be achieved through
adjusting the electric field intensity while keeping the fiber grating length, periodicity and the other parameters as
constants.
Output power stabilized dual-order Raman fiber laser by generated amplified spontaneous emission
Show abstract
A dual-order Raman fiber laser (RFL) is numerically presented with suppressed low-frequency relative-intensity-noise
transfer from pump sources to both the first- and second-order Stokes output. It is accomplished by generating the
amplified spontaneous emission near second-order Stokes shift from the launched pump. Their powers can be tuned in a
large dynamic range. Besides these, the low-power second-order Stokes output is also stabilized in the RFL setup. These
special behaviors fit the proposed RFL for use as dual-order pump sources in Raman fiber amplifiers.
Direct design of super-narrowband fiber grating filter with discrete layer-peeling algorithm
Show abstract
Combined DLP algorithm and sampled theory, super-narrow FBG filter for arbitrary shaping spectrum can be
successfully synthesized, and the process of design and fabrication using one uniform mask are demonstrated. A novel
method for a single stage illumination to fabricate dc-free apodized sampled FBG is proposed based on the chirp of
sample period. Above design and fabrication method are testified by simulation and experiment results, and a super-narrowband
triangle shaping FBG filter with 25pm 3dB bandwidth and side lobes suppression beyond 20dB is
fabricated.
Thermal stress effects of the interlayer between waveguide cores in buried channel optical waveguides
Show abstract
It is well known that the thermal expansion coefficient of the cladding layer can significantly influence the stress induced
birefringence in arrayed waveguide gratings. For the first time, the so-called cladding layer is divided to two parts, i.e.
upper cladding and interlayer. The effects of the thermal expansion coefficient, the Young's modulus and the Poisson's
ratio of the interlayer, the upper cladding layer and the buffer layer on thermal stresses in buried channel silica-on-silicon
optical waveguide cores are studied by use of finite element simulation. The results show that the interlayer between
waveguide cores plays the most important role in determining thermal stresses of waveguide cores. The influences of the
upper cladding layer and the buffer layer are small, though the former affects slightly larger than the later. By adjusting
the thermal expansion coefficient of the interlayer instead of the cladding layer, it is faster to minimize the stress induced
birefringence, and the thermal stresses around waveguide cores are almost symmetry. It is also shown that the thermal
stress effects of the thermal expansion coefficient and the Poisson's ratio on the cladding layer can be considered as
linear superposition of those on the interlayer and the upper cladding layer. However, this conclusion is unsuitable for
Young's modulus because of big coupling effect when the thermal expansion coefficient of the interlayer is large.
Exceeded 1W average power, 1kW peak power, and all-fiber nanosecond Yb-doped amplifier
Show abstract
We report on the fiber-based amplification of a commercially packaged, fiber-pigtailed-pulsed diode laser operating at
wavelength of 1064nm (bandwidth 0.45nm). The cascaded Yb-doped fiber amplifier can operate safely by using
cascaded Wavelength division multiplexing (WDM) in each single-mode amplification stage. The total isolation of
cascaded WDM can protect the laser diodes from destroyed by feedback of optical power. At repetition rate of 50kHz,
pulse duration of 20ns, and average power of 0.5mW, output power up to 1.05W And peak power up to 1.05kW are
obtained, with a high signal to noise ratio of 20dB. The whole system is a good choice for a preamplifier of high-power
short-pulse amplification. The aim of the experiment is to study the design of preamplifier for high-power short-pulse
amplifier via cascaded fiber-based amplifier.
Dielectric properties of GaAs in terahertz wave
Show abstract
The terahertz dielectric properties of GaAs were tested in the frequency range extending from 0.23 THz to 0.375 THz by
using backward-wave oscillator (BWO). The terahertz refractive indices, the absorption spectra and the dielectric
functions of various resistivity GaAs were measured and compared. The experimental results indicate that the absorption
coefficient of the GaAs is decreased with the frequency increasing and its least absorption coefficient equals 3.87x10-4
cm-1. Our results demonstrate that the applicability of the backward-wave oscillator THz absorption spectroscopy to
GaAs characteristic analysis by calculating the absorption spectra. This work establishes the basic spectra data for GaAs
is very significative to design the high efficiency terahertz wave antenna.
Compact optical modulator based on slow-wave waveguide
Show abstract
In this paper, a compact optical modulator using negative refractive material slow-wave waveguide is proposed. The
finite element method (FEM) has been employed to analysis the performances of the novel modulator. The results show
that the size of the novel optical modulator has low power consumption, compact size, easy fabrication, and the cost. Its
dimension is only 40μm-long. The size of the novel optical modulator is 100 times shorter than that of the conventional
lithium niobate optical modulator. It has a potential application for future optical communication systems.
Fiber grating laser pressure sensor
Show abstract
In this paper, a pressure sensor based on distributed Bragg reflector (DBR) fiber laser
was reported. The laser was operated in single longitudinal mode. For the longitudinal-mode has
two orthogonal polarizations, external press on the cavity would induce birefringence. It can be
used to sense external pressure by measuring the beat frequency shift of polarization mode. After
theoretical derivation and experimental verification, the sensing characteristics of the laser were
shown in detail.
A novel joint-matching method for optimizing the compatibility between optical source and en/decoder of OCDMA
Show abstract
Optical en/decoder is one of the key components in Optical Code Division Multiple Access (OCDMA) systems.
Therefore, the improvement of performance of en/decoder is very necessary for improving the whole performance of
OCDMA system. Among all kinds of factors which affecting the performance of en/decoder, the compatibility between
optical source and en/decoder is proved to be an inevitable item. In this paper, as to equivalent phase shift super-structured
FBG (EPS-SSFBG), an advanced en/decoding technology, both optimum pulse width and proper central
wavelength deviation between optical source and EPS-SSFBG based en/decoder are first investigated, which lead to a
novel method of optimizing the compatibility between optical source and en/decoder. The simulation results show that
there exists an optimum pulse width, not the narrowest one, fit for EPS-SSFBG based en/decoder, what's more, it is
proved advisable that proper central wavelength deviation would be beneficial when pulse width is relatively wide.
Simulation and experimental results prove the feasibility and effectivity of the proposed method.
High-frequency ultrasound measurement using fiber grating laser hydrophone
Show abstract
A fiber laser hydrophone system for measuring tone-burst ultrasonic signals up to 40 MHz is developed. The hydrophone
consists of a cladding-etched dual polarization distributed Bragg reflector (DBR) fiber laser. The sensing mechanism is
based on the modulation of the fiber laser's birefringence induced by the ultrasonic pressure. The ultrasonic signal
waveform is demodulated using an FM-DEM (frequency modulation-demodulation) circuit and measured with a digital
oscilloscope. Incorporating the time delay measurement of ultrasonic signal, this fiber laser hydrophone system achieves
a spatial resolution of 37.5 μm at 40 MHz.
Fiber Bragg gratings with refractive index direct current component modulation
Show abstract
We propose a simple method for achieving a desirable chirp in the grating based on refractive index direct current
component (RIDCC) modulation. The method uses dual-scan technique with an UV beam to obtain an increase of
refractive index direct current component in the grating along the grating length. The effect of RIDCC modulation on the
group delay characteristic of fiber grating is analyzed and the relationship between the RIDCC modulation and group
delay of grating is deduced. Also, the numerical simulation results are given by using coupled mode theory and they
agree very well with theoretical values. By controlling the RIDCC modulation function and modulation coefficient, we
can realize different group delay profile using the same phase mask. These gratings can be used to compensate
dispersion and dispersion slope of transmission fiber in high-speed optical communication systems.
Simultaneous measurement of surrounding temperature and refractive index by the tilted fiber Bragg grating
Show abstract
Simultaneous independent measurement of surrounding refractive index (SRI) and temperature using
the tilted fiber Bragg grating is proposed and experimentally demonstrated. Core mode is sensitive only to the
temperature while cladding modes are sensitive to the temperature and SRI, theirs temperature sensitivities are
equal. The wavelength shifts of two kinds of modes with a change of temperature and SRI allow for simultaneous
discrimination temperature and SRI effect. In addition, the sensitivity of TFBG to SRI is significantly enhanced by
hydrofluoric etching clad; it can satisfy the custom-built sensitivity that the clad of TFBG was etched in different
degrees as well. This sensor is potential for chemical-biochemical sensing application and measuring the
concentration of the chemical solutions accurately.
Tm3+-doped silica fiber laser output at 1.94um with multi-mode FBG as cavity
Show abstract
An all-fiber LD-clad-pumped Tm-doped fiber laser was reported, and the CW maximal output power reached 24W at
nearly 1.94µm. The homemade double-clad Tm3+-doped fiber had a demission of 25/250µm with the core NA 0.13 and
inner-clad NA 0.46. A matched passive multi-mode FBG acted as the front cavity. The cavity was build-up by the high
reflectivity FBG and fiber end Fresnel reflectivity. The all-fiber scheme was build-up by splicing the pigtail fiber, FBG
fiber and Tm3+-doped fiber. Cooling by the water, the 56% high slope efficiency was achieved and threshold was 6.4W,
respected to the launched pump power. When the output power was less-than 3W, the output laser was single-peak
operating at 1936.4 nm with a very narrow linewidth (50 pm) laser output. Increasing the launched pump power, the
output laser wavelength grew to 3~4 peaks. The multimode fiber Bragg grating (FBG) transmission spectrum was also
measured with a matched 82cm Nufern Tm3+-doped fiber as fluorescent sources. With the dichroic and the FBG building
up cavity, the output laser characteristics were also investigated. Because the multi-mode FBG reflectivity was not very
high, both ends of the fiber laser had laser output power, and the ratio was nearly 10:1. As we know, it was the first time
to report the multi-mode FBG all-fiber laser. Under this simple Tm3+-doped fiber laser scheme, we estimated that the
maximal output power could reach several ten watts.
Analysis of a new measurement for electromagnetic field with the DGD of fiber grating
Show abstract
Fiber grating is sensitive to the stress, temperature and other entironmental factors. It has caused much attention and has
been used widely. In this paper a new magnetic field measurement using different group delay (DGD) of fiber grating is
proposed. When the magnetic field applied the refractive index difference of the two circularly polarized light in fiber
grating will be changed because of the faraday effect. So the DGD of fiber grating is changed. Through the formula
derivation in certain condition, the linear relationship between the peak value of DGD and magnetic field in
measurement range is found. Through the simulations the effect of applied magnetic field, fiber length and index
modulation coefficient on the peak value of DGD is shown. On the other hand, the linearity will tend to saturation when
magnetic field exceed the measurement range. So we can determine the mesurement range given design parameters. In
the experiments the DGD of FBG without and with magnetic field are performed. The peak value of DGD increases with
the applied magnetic field linearly. The fit curve of experimental and simulated results is parallel approximately and the
gap is because of the intrinsic DGD of fiber grating. Using the optical vector analyzer with precision of 10-5ps we get the
sensitivity of 0.001Gs in experiment. The simulations and experiments validate this method.
Study of the highly dispersive dual-core photonic crystal fiber with large mode area
Show abstract
The very high dispersive dual-core photonic crystal fiber is analyzed by the full-vector finite element method. The
dependence of the phase-matching wavelength (PMW) and the full width at half-maximum (FWHM) on the refractive
index of the doped inner core, the diameter of air holes and the hole pitch is demonstrated. The dispersion value is as
large as -1427 ps/(nm km) and the effective mode area of the fundamental mode, 82.06 um2 are obtained.
Investigations on beam-shape transformation by direct inscribing an index modulation pattern on optical fiber surface
Show abstract
End surface grating by direct inscribing an
index modulation pattern on optical waveguide surface to
control amplitude and direction of the diffracted light is
fabricated. Direct inscribing an index modulation pattern by
femto-laser is simple, agile and the pattern is steady and
durable. We control power and direction of diffracting orders
by inscribing different modulation patterns and the
controllability may well offer opportunities for various kinds
of applications such as beam splitter, beam deflector, and
beam shape controller.
Dual-wavelength erbium-doped fiber ring laser based on one polarization maintaining fiber Bragg grating in a Sagnac loop interferometer
Show abstract
Dual-wavelength with orthogonal polarizations erbium-doped fiber ring laser at room temperature is proposed. One
polarization-maintaining fiber Bragg grating (PMFBG) in a Sagnac loop interferometer is used as the wavelength-selective
filter. Due to the polarization hole burning (PHB) enhanced by the PMFBG, the laser can operate in stable dual-wavelength
operation with wavelength spacing of 0.336 nm at room temperature by adjusting a polarization controller
(PC). The optical signal-to-noise ratio (OSNR) is over 52 dB. The amplitude variation in nearly one and half an hour is
less than 0.6 dB for both wavelengths.
Solid-core photonic bandgap fiber with polymer coating for biosensing applications
Show abstract
In order to achieve photonic band-gap effect as sensing mechanism and improve biocompatibility of relatively lower-cost
silica-core phonic crystal fibers (SCPCF) and make use of photonic band-gap effect as sensing mechanism, polymer
with similar biocompatibility as PMMA coating in SCPCF air-holes is proposed in this paper. In order to evaluate the
polymer coating effect, a three-layer model of air hole is proposed. The wavelength shifts of photonic band-gap edges
(PBEs) were evaluated by plane wave expansion (PWE) method, assuming refractive index of silica ns, polymer np and
air na are 1.45, 1.50 and 1.00 respectively. Blue shifting of bands are observed in the simulation and the bandwidth of
each band-gap becomes narrower with the increasing of air ratio. The result shows that 1nm change of air hole is able to
obtain a wavelength shift of 0.43nm. Assuming the wavelength shift of 0.01nm can be detected, a small air hole variation
of 0.023nm can be measured.
Glucose optical biosensor with sol-gel-coated long-period gratings
Show abstract
Sol-gel entrapment technique is proposed for glucose oxidase immobilization in long period grating glucose sensor. The
glucose oxidase is encapsulated in transparent sol-gel matrix to detect the presence of D-glucose molecules. A sensitivity
of 39.8mM/nm was achieved for the fabricated glucose biosensors.
Ring-cavity Er/Yb co-doped fiber laser and its mode characteristics
Show abstract
A ring-cavity Er/Yb co-doped fiber laser (EYDFL) was designed and the characteristics was studied in this paper. It used
1064nm Nd:YAG laser as its pump, and the gain medium is a 4.1m-long EYDF. The single longitudinal-mode operation
is realized by introducing a fiber Bragg grating (FBG) as narrow wavelength-selective element, and a section of EDF
not-pumped as saturable absorber. The fiber laser resonator has been optimized, and the stable laser output with single
longitudinal-mode was got. In the simulation and experimental study, the difference of fiber laser output power using
output coupler in different coupling ratio has been studied. The optimal coupling ratio testified in experiments was near
80 percents. The effects and influences of saturable absorber on characteristics of output laser mode are analyzed.
A simple in-line fiber polarizer based on tapered flat-clad microfiber with a liquid cladding overlay
Show abstract
A novel and simple in-line fiber polarizer is presented. The proposed device is fabricated by tapering an
anisotropic flat-cladding birefringent micro-fiber surrounding with low-dispersion optical-liquid cladding. We also
presented a theoretical analysis for dispersive birefringence of flat-clad micro-fiber with liquid overlay. The proposed
device can be useful as all-fiber polarizer for optical communications. Simulation results show the birefringence of the
device can be enhanced when the aspect is larger. In the experimental measurement for polarization extinction ratio
(PER) of the proposed device, a fiber-pigtailed 1549.25 nm DFB laser light was used as light source. The PER about 30
dB was demonstrated when the liquid with refractive index nD = 1.45 was used.
Improvement of optical characteristics of holey fibers and their applications
Show abstract
We fabricate versatile holey fibers with 6-hole, 18-holes in order to improve their property in terms of
bending insensitivity. The fabricated holey fibers are applied for connection and integration for
compact optical devices.
Design and simulation of microring resonators for time-domain optical add-drop multiplexing
Show abstract
A time-domain optical add-drop multiplexing (OADM) technology using microring resonators is reported. Design and simulation are presented. The microring resonator is predicted to be fabricated by using Pockler electro-optic materials. The microring resonators possess a multistage-cascaded structure to satisfy the requirement to generate switching windows. Cascaded coupled microring resonator can expand the single resonant point into a box-like resonant region and reduce the wings of resonant curve. While multistage resonators are used and a certain shift of the resonant region is arranged between the stages, the total resonant region can be expanded further. We achieve the shift of the resonant region between the two stages by selecting different ring radii. The resulted microring resonators possess a box-like characteristic with shape wings. The OADM includes two microring resonators (MMRs) driven by sine wave voltages, one is used to accomplish the add function the other is used to accomplish the drop function. The only operation differences between the two MMRs are the bias voltage and the phase of the driving signal. The OADM only requires electrical control signal and simple structure instead of high-quality optical control pulse and interferometer structure. FDTD simulation results show that the resonators can stratify the requirements to generate complementary switching windows for OADM operation.
Investigation of aluminum wire-grid polarizers for visible wavelengths using rigorous coupled wave analysis
Show abstract
In this study, we model and compare the performance for several different metal wire-grid polarizers over the visible
spectrum using rigorous coupled wave analysis and determine that the best choice for the wire material is aluminum.
However, a layer of Al203 forms rapidly on the aluminum wires even in high vacuum. The effect of metal oxide layers
forming on the wires is also modeled. It is shown that the actual oxide layer forming on the wires has only a small effect
on the performance of the polarizers. With the oxide layers coated on the wire, the transmission coefficient is nearly
invariable, extinction ratio slightly decreases. Next, the polarization properties are considered with changes in the
physical parameters, including period, metal height, duty cycle, and angle of incidence. The results show that aluminum
wire-grid polarizer has high transmission coefficient and extinction ratio over visible spectrum, as well as uniform
performance with wide variations in the angle of incidence. These features with their small form factor make it desirable
for use in field-of-view and allow more compact component designs.
Quarter wave plate made by cutting straight holey birefringent fiber
Show abstract
Compact samples of quarter wave plate have been fabricated respectively by cutting holey birefringent fiber and
conventional birefringent fiber into different length of short sections. The temperature instability and wavelength
sensitivity of these samples are analyzed and measured. The influence of fiber length and fiber prototype on the
retardation variation is compared. The retardation deviation almost linearly increases with the fiber length of samples.
Compared with the sample made of conventional birefringent fiber, the temperature stability of the sample made of holey
birefringent fiber is greatly improved by one order, but the wavelength bandwidth needs to be further expanded by
optimizing the holey cladding structure.
Influence of extension lead and input polarization state on performance of quarter wave plate made by increscent-spinning birefringent fiber
Show abstract
The influence of extension lead at both sides and input polarization state on polarization transform performance of
increscent-spinning birefringent fibre is calculated and examined. In the extension lead, the output polarization state is
fluctuating with period relevant with the max-spin-rate or the beat length of birefringent fiber. It is found, the optimal
input polarization state for the best output linear polarization is not the ideal circular polarization but a elliptical
polarization related with the maximum spin rate, the optimal input linear polarization orientation is not in line but has a
slight divergence angle with the birefringent axes of fiber, and if the input linear polarization is not perfect linear
polarization, the output circular polarization would be nonlinearly degraded. These results have advisable meaning for
the design, test and evaluation of the quarter wave plate made by the increscent-spinning birefringent fibre.
Fabry-Perot etalon in hole-type photonic crystal as an optical sensor
Show abstract
A Fabry-Perot (FP) etalon constructed in a two-dimensional photonic crystal (2D PhC) utilizing self-collimation effect is
proposed and investigated. The 2D PhC consists of a square lattice of air holes in silicon. It has square-shaped equal
frequency contours (EFCs) in the frequency range of 0.275-0.295c/a for TE modes. The FP proposed consists of two
PhC reflectors and one cavity between them. Light propagates in the photonic crystal employing self-collimation effect.
The two reflectors have reflectivities of around 97.5% in the frequency range 0.275-0.295c/a. The FDTD calculation
results show that the transmission spectrum of the FP etalon has a uniform peak spacing between 0.275c/a and 0.295c/a.
The transmission spectrum shifts to the lower frequency as the refractive index of a fluid filling in the air holes in the FP
cavity is increased. Therefore this etalon can work as an optical sensor for a gas and a liquid. The fluids whose refractive
index vary within 1.0-1.5 can be sensed and detected. Its dimensions are only about tens of microns when the central
operating wavelength is equal to 1550nm. So it can be applied as a micro-scale sensor.
High power tunable and passively mode-locked erbium-doped fiber ring laser based on nonlinear polarization rotation
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Using the nonlinear polarization rotation technique and an Er3+/Yb3+ co-doped fiber amplifier, we have
experimentally obtained high output power wavelength continuously tunable laser and high output power passively
mode-locked pulse in an erbium-doped fiber ring laser.
All-optically tuned delay characteristics of fibre Bragg grating
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Based on the nonlinear coupled-mode equations (NCMEs) of fibre Bragg grating (FBG), all-optically tuned delay is
realized in two linearly apodized FBGs in simulation. The characteristics of tuneable delay under the control of input
optical power are analyzed, and the sensitivity of delay time with optical power is discussed. Results show that the delay
maximum can be obtained at the optimal points in connection with input power, operating wavelength and grating
length.
Fabrication of photosensitive polarization-maintaining erbium-doped fiber and application for fiber laser
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A new method of fabricating Panda-type photosensitive polarization-maintaining erbium-doped fiber(PM-EDF) is
proposed and demonstrated. A sample of PM-EDF is fabricated using this method and an exhaustive analysis is made
about the characteristics of PM-EDF, the results shows that this method is practicable. Two fiber Bragg Gratings (FBGs)
are written into PM-EDF directly as the lasers reflectors, a three-states-tuned fiber laser is then obtained using a
polarization controller (PC).
Design and experiments on multiwavelength fiber lasers
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A simple multi-wavelength erbium-doped fiber laser with narrow-line-width lasing output was proposed and
demonstrated using fiber Bragg gratings and Arrayed-Waveguide Gratings (AWG). Wavelength competition was
naturally prevented in this kind of laser by using AWG in the linear-cavity. As an example, a triple-wavelength erbium-doped
fiber laser was experimentally investigated. Using the laser scheme, the proposed laser can laser three
wavelengths simultaneously. The fiber laser retrieved the optical side-mode suppression ratio of over 50dB and the
average output power of -10.714, -10.649 and -10.578dBm at 1554.710, 1555.516 and 1556.421nm, respectively. And
the 3-dB bandwidth of each laser was less than 0.010nm. Moreover, the output power stability of the laser had also been
measured and analyzed. Experiment results showed that the laser can be operated stably in narrow-line-width with
single- and triple-wavelength output at room temperature.
Wavelength tunable single freqeuncy bistability erbium-doped fiber ring laser
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In this paper, a tunable single-frequency fiber laser is designed. For narrow linewidth and single frequency
operation, a length of 2.75m unpumped EDF as a saturable absorber is used. The FBG combined with the unpumped
EDF provides narrow frequency selection. Counter propagating beams in the unpumped EDF form a standing wave
that results in periodic spatial hole burning. This creates a narrower bandwidth absorption grating than the FBG. The
output laser wavelength can be changed from 1530nm to 1570nm by the FBG. The 3dB spectrum width of output
laser is 0.08nm and the side mode suppression ratio is 55dB. The maximum output power exceeds 12mW, and the
stability is less than ±0.005dB. A nice single-frequency laser is observed. From the relationship of the pump power
and output power, it is obvious that the optical bistability switchable phenomena is showed in output characteristics.
The bistability switchable phenomena is caused by the saturable absorber in the ring cavity. A 10Gb/s codes rate is
used in the fiber laser transmission experiment. The high speed optical signal is transmitted in long distance without
regeneration. The eye diagrams of optical transmission are measured, the performance of long haul transmission
with high speed modulation is perfect.
A low-loss broadband y-branch for fiber to the home applications
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A low-loss broadband Y-branch for fiber-to-the-home applications is presented. Smaller waveguide height is utilized for
the potential of better deposition of the upper-cladding. A multimode section allows broadband operation. Simulation
results show good performance in the wavelength region from 1200nm to 1700nm for FTTH systems.
A high-performance aluminum wire-grid polarizer for the optical telecommunication applications
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In this study, we propose a high-performance polarizer with Aluminum wire-grid structure that an antireflection layer
(AR) is deposited between the metal wires and the transparent substrate. The polarization properties of the polarizer are
analyzed in detail using rigorous coupled wave analysis (RCWA). The theoretical research shows that aluminum wire-grid
polarizer has high transmission coefficient and extinction ratio in near infrared, as well as uniform performance with
wide variations in the angle of incidence. For the fiber communication window of 1550nm, the transmittance and the
extinction ratio are 95.4% and 35.3dB, respectively. Furthermore, a layer of Al203 forms rapidly on the aluminum wires
even in high vacuum, the effect of the metal oxide layers on the polarization properties is modeled and analyzed. The
results have shown that the polarizer with oxide layers coating on the wires still provides high performance. These
features with their small form factor make it has potential for use in many integrated optical applications.
Short cavity single-mode dual wavelength fiber laser array
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In this paper, a short polarization-maintaining Er:Yb co-doped fiber laser is experimented. A pair of FBGs are
written in the Er:Yb co-doped sensitive fiber using UV beams. A 976nm pumping laser diode is used, and output
wavelength is selected by two FBGs. The PM Er:Yb co-doped fiber is used to main the orthogonal polarizations SM
lasing stability. The SM operation in each wavelength has been verified. On the basis of previous short cavity fiber,
a simple DBR dual wavelength fiber laser array has been designed and experimented. Two sections of short Er:Yb
co-doped fiber cavities are pumped by a 976nm LD simultaneously. The pump laser is splitted to pump each Er:Yb
co-doped fiber. It used a WDM coupler at 1550nm to connect the output port of two DBR fiber laser, an isolator is
spliced to the common arm of the WDM and used as the output port. The dual wavelength spacing is 0.31nm. The
output power reaches 6mW with the optical signal to noise ratio of greater than 30dB. A 12.5Gb/s codes rate is used
in the fiber laser transmission experiment. A nice optical eye diagram is recieved after long distance single-mode
communications fiber transmission.
Multiwavelength fiber ring laser based on an SOA and Lyot birefringent filter
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This paper presents a detailed study on Wavelength Division Multiplexing - Passive Optical Network (WDM-PON)
light source of spectrum sliced multiwavelength fiber ring laser and simple optical Lyot filter. First, the principle of the
Lyot birefringent filter for comb generation of the multiwavelength laser is theoretically analyzed. Then we incorporate
the Lyot filter and a semiconductor optical amplifier (SOA) as the gain medium into a ring laser cavity. Finally, we
experimentally demonstrate an SOA based multiwavelength fiber ring laser using Lyot birefringent filter.
Multiwavelength operation up to 25 laser lines with the signal-to-noise ratio over 30dB and 0.8nm wavelength spacing
was demonstrated. The power equalize is within 2 dB and the line width 0.108nm is close to the equipment resolution.
This multiwavelength laser source has also been proved to have good stability after consistently 90 min time evolution.
In general, this multiwavelength laser source has the advantage of simple structure, multiwavelength operation, high
SNR and good stability.