The fanning and the two-wave mixing properties of Ce:KNSBN photorefractive fiber have been studied. The fanning exhibits a strong nonlinear dependence on the incident angle, which differs not only from the bulk Ce:KNSBN crystal but also from the reported photorefractive fiber of other materials. The two-wave coupling gain is also strongly pump beam incident-angle dependent, restricted seriously in a narrow incident angle range, which is attributed to the internal reflection from the side-surface and the fanning effect as well. The numerical fitting method is adopted, which shows to be coincident with the experimental data. The photorefractive fibers have potential applications in signal amplification, holographic storage and phase-conjugation, especially incorporation into optical fiber systems.

A mathematic model about split ratio and polarization crosstalk of polarization-maintain fiber couplers have been built and the experimental study has been done. The result showed that the split ratio and polarization crosstalk both varied with the temperature and the variation is linear approximately. The split ratio variation due to the induce light polarization orientation change was measured too. Experimental result were coincident with the theory model exactly.

We report the periodic filtering properties of a side- polished single-mode fiber-to-MMOW coupler using a polished LiNbO₃ overlay waveguide. The tuning behaviors by thermo-optic effect of an IMCL with a photopolymer have been demonstrated. A possibility to be used for multi-channel isolation filter of WDM and multi-channel light source is investigated. The coupling phenomenon with an IMCL and without an IMCL is simulated and compared to the experimental results. The output spectra of this filter show a free spectral range with 4nm when the X-cut LiNbO₃ with 200 μm thickness are used to an MMOW. This filter was applied to a fiber ring laser and tunable dual- wavelength operations have been demonstrated.

We discuss the propagation characteristics of the electromagnetic field in the symmetric metal-clad planar uniaxial crystal waveguide. For the special waveguide structure that the optical axis of the crystal is on the x-z plane, where x is the normal direction of the waveguide plane and z is the propagation direction, we obtain the analytic accurate solution of the modal fields. It is shown that:(1) there are TE mode and TM mode in this special waveguide structure; 2) The direction of the wave vector and the Poynting vector of TM mode are not collinear; (3) The principal mode of the waveguide is the principal mode of TE mode for the negative uniaxial crystal, but the one of TM mode for the positive uniaxial crystal.

The relationship between crosstalk of an arrayed waveguide grating (AWG) and the parameters such as the width of the waveguide, the pitches of output waveguides and the number of waveguides in the array were studied theoretically and numerically in this paper. The beam propagation method (BPM) was used for numerically investigating the crosstalk. The simulation results show that when the pitches of output waveguides is small, the crosstalk is mainly dependent on them. However, when they are large enough, the crosstalk is caused mainly by the sidelobe level of the focal field at the image plane. The results also show that choosing a suitable number of the arrayed waveguides is more effective than only increasing it. The impact of the width of the waveguide on the crosstalk is also studied.

In this paper, the propagation characteristics of the fields in a planar waveguide, a synchronous-waveguides and a s-bended waveguide were simulated with the Finite Difference Time Domain (FDTD) method. The distribution graphs of the field intensities for the simulated optical waveguides were obtained. Coupling lengths were gained from the data of graphs. By comparing these results with that simulated with beam propagating method (BPM), it is concluded that during simulating waveguide with relatively simple structure the simulation performed by the FDTD method are better in accord with the BPM analysis, but with relative complex structure such as the s-bended waveguide the FDTD method can simulated much better than the BPM dose. So during simulating waveguide with complex structure the FDTD method is the better option.

Thin film optical waveguide and 1micron polystyrene sphere array mixed system was fabricated and characterized experimentally. The attenuation coeffecients for 10, 5, 2 and 1micrometers 0 polystyrene micro-sphere linear and curvilinear array were measured to be 0.51, 0.48, 0.78, 0.98dB/sphere and 0.71, 0.67, 1.09, 1.30dB/sphere, respectively. In the MSF system for the 1micrometers 0 polystyrene micro-sphere linear and curvilinear array, the attenuation coefficients were measured to be 1.17 and 1.41dB/sphere. And the attenuation coefficients for linear and curvilinear optical thin film waveguides in the MSF system increased more than the waveguide without the sphere. In MSF waveguide at 1micrometers rule, evanescent wave interaction between optical thin film waveguide and polystyrene micro-sphere array was expected.

The acousto-optical tunable filter (AOTF) play a key role in the dense WDM systems. In this AOTF, tow parallel acoustical waveguides compose of a directorial coupler of surface acoustic wave (SAW). By using partial acoustical absorbers, we control the distribution of the acousto-optical coupling strength along the optical waveguide to appear four decaying lopes, and make the mode conversion characteristics of the filter approach to the ideal rectangular function. The calculation results show that the -1dB bandwidth of the filter is 3.9nm, the -10dB bandwidth is 5.2nm, the interval from,-DB to -1dB is only 0.63nm. So several optical wavelengths can be simultaneously filtered with only one RF frequency.

Integrated Acoustooptical Tunable Filters (AOTF) have great potential application in WDM optical networks because of some advanced properties, especially the unique property of simultaneous multiwavelength filtering. In this paper, we have developed time-dependent coupling mode equations with multiple acoustic waves travelling simultaneously. Take four acoustic waves as an example, we have shown some numerical results of conversion characteristics based on the developed coupling mode equations. We have also analyzed the fluctuation of the main peak, the center wavelength and the full width of half-maximum (FWHM) with respect to time. After discussing the drawbacks of the collinear AOTF in multiwavelength operation, especially the serious distort of conversion characteristics and the high crosstalk for narrow channel spacing, we propose for the first time that the conversion characteristics of AOTF can be improved by using quasi-collinear acoustooptical filters.

The structure parameters and the Ti-diffusion parameters of the Integrated Optical Polarization Splitter (IOPS) affect the performance of the device greatly. By discussing these two factors quantificationally and comprehensively, we obtain a series of theoretical conclusions, which are important guidance to fabricate high-performance splitters. In particular, because of the limitation of the lithophotographical technique, there must be a flat at the end of the V-shape between the branch waveguides of the IOPS. The flat has crucial effect on the optimization procedure of the structure parameters. We have analyzed the interaction between the width of the flat and other parameters in an IOPS, which is not discussed in previous papers. Technological parameters' affection on the structure optimization is also discussed. In addition, we have fabricated a series of splitters, which have optimized TE and TM splitting ratios of 28dB and 25dB. Through experimental measurements, we have validatedthe theoretical calculations.

The self-injection locking single frequency Yb-doped fiber ring laser is reported. The system shows compact, stable and tunable. In the primary experiment, the Self-injection locking single frequency fiber ring laser with wavelength 1.05325)mum, power exceeding 3.5mW,line-width less than 36 MHz was manufactured. The laser shows stability, low threshold and high power. No mode-hopping was observed within 2 hours. The single polarization output can be obtained when use single polarization fiber.

A diode-pumped, compact, wavelength tunable, single frequency Er³⁺:Yb³⁺ codoped DBR fiber laser is reported. An output power of 2.4mW for 75mW of 980nm diode pump power and a slope efficiency of 6% at 1557.05nm were obtained. Linewidth of the laser was estimated at 1557.05nm to be less than 1MHz. Also, the laser can be tuned to wavelengths between 1557nm to 1561nm and operates single mode throughout this range.

In this paper, high-density and large-capacity parallel data reliable transmission has been accomplished in high electro-magnetic interference environments via virtual- parallel optical transmission technique. Through time division multiplexing (TDM), all the parallel data signals and control signals are converted to high-speed serial data stream. Each bit is transmitted in a time slot during a frame period Thus, the parallel signals can be transmitted using only one opto-electronic device. Each optical transmission channel consists of two optical fibers, can achieve full-duplex transmission of 24 bits parallel signals. The maximum frame rate is 75 MHz. This data transmission card can be expanded to 6 channels, has a maximum data throughput of 15 Gbps. This optical data transmission link can work properly for a wide range of supply voltage. When the supply power voltage varied from 4.2 to 7.0 volts, the bit error rate (BER) is still below 10E-12.

Conditions to reconstruct pulse intensity and chirp from autocorrelation signals are discussed. The interferometric SHG autocorrelation signal and the interferogram of fundamental light are shown to be sufficient data set for the pulse form retrieval. The method utilizes Fourier analysis of the signals and iterative calculations.

A kind of specially sampled fiber Bragg grating (SSBG) has been recently proposed to compensate the dispersion in the optical fiber communication system. We substitute dispersion compensation fiber (DCF) with SSBG in the 10Gbit/s dispersion-managed system over 1000km. Post- and pre-compensation methods are compared. The dispersion compensation effect of SSBG is also compared with the chirp Bragg grating (CBG).

An intersecting wave guide has a high extinction ratio, low loss, and wavelength independent characteristics for an acousto-optic tunable filters (AOTF). An oxide film-loaded surface acoustical wave guide (SAWG) has a strong confinement, excellent filter characteristics, and provide high design flexibility. In this paper we present a numerical method for an oxide film-loaded SAWG on a substrate. The result is agreed with the experiment.

A new pump configuration of two steps of cascaded Raman fiber amplifier is demonstrated and is numerically simulated in the 80 km fiber span. In order to obtain lossless transmission and low noise figure, the pump power values are optimized.

Based on the theory of nonlinear Optics and phase conjugate Optics, we pointed out that in the WDM communications systems, most of effects, such as: chromatic Dispersion, loss, SRS, SPM, XPM, PMD as well as FWM can be eliminated by a device, OPC. We also showed that, for dispersion cancellation only needs the conjugated wave propogates same distance as signal wave does. However, for nonlinear effects cancellation the intensity adjustment are necessary, since they are depending on signal intensity in other channels or polarization direction. For random polarization mode coupling and FWM cancellation also need to meet the beat condition.

This paper reports a new monitoring system with the fiber- optic sensors that embedded in composite material. The system can be used for the structural health monitoring of composite material. As the etched fibers embedded in composite material are acted upon by the internal stress of the material, the light signals traveling in the fibers will decrease or vanish. The fibers are embedded in composite material perpendicularly to build a 2-D fiber optic sensor array that can determining the locations of the structural damages in the composite material. The paper discussed the photoelectric transformation by a CCD and the photoelectric signal processing. The results of the real-time monitoring are given.

The temperature effect of fiber optics Raman back-scattering have been researched at high temperature (1000 degree(s)C) condition. A distributed fiber optics Raman and Rayleigh back-scattering sensor measuring network have been design and fabricated. The performance of high temperature measuring network is following: temperature measuring range: 0-1000 degree(s)C; temperature uncertainty: <+/- 30 degree(s)C; temperature resolution: 1 degree(s)C; Spatial resolution: 8<m Measuring time: 40s; Fiber length: 100m-10km (according to user need). The stress change of optical cable can be toke out by the measuring network.

This paper described a 1:4 demultiplexer in a standard 0.25 micrometers CMOS. A tree-type structure is used to reduce the clock frequency and the SCL (Source Couple Logic) is used to construct high speed DFF. The chip occupies 1mm² area. It consumes 683mW from a 3.3 V supply. The operating bit rates is higher than 10Gb/s.

Frequency chirp characteristics of wavelength converters based on cross-gain modulation (XGM) in a semiconductor optical amplifier (SOA) is analyzed with a theory analytical model. The numerical simulation results show that the input pump power and probe power, the probe wavelength and the pump wavelength have direct influence on the chirp characteristics. We found that the output pulse of the converted light undergoes a blue shift during the rising edge and a red shift during the falling edge. In order to reduce the frequency chirping, high probe power, low pump power, and appropriate wavelength region of the signal and the probe are favorable.

The reliability is one of the most important performance indices to evaluate the optical fiber network. In this paper, a novel method with a membership cloud model is put forward to assess the network reliability, and a membership cloud model is a method belonging to fuzzy mathematics. Combined with the industrial network features, on the basis of a membership cloud, the tree-like network reliability is evaluated. This method has universal significance in revealing the transformation law between qualitative and quantitative knowledge.

A novel Dedicated Multimedia Fiber Industrial Network (FIN) established by consulting the protocols and standards of FDDI-II satisfies the specific requirements of real-time transmission. In this paper, the characteristics of services in FIN are analyzed and the services are classified according to the definition of the Isochronous and Packet ones. Basing on the service partition, the requirements for bandwidth of services are analyzed, and structures of the Cycle Frame and the Token are determined. In the end, the flow charts of transmitting and receiving Cycle Frames in FIN are presented, and the data transaction results of the sub-layers are simulated.

Optimal design of the parameters in dispersion compensation fibers (DCFs) is studied in this paper. The mathematics model of the DCFs with three-claddings is founded. Then the intrinsic function is derived. The dispersion is obtained numerically by computer simulation. Last the effects of different parameters on dispersion are discussed and analyzed in detail.

This paper focuses on a scheme for resource provisioning control at nodes in the WDM backbone. Taking note of that allocation of wavelength is only for duration of the burst, and the allocations to connections can be less than a wavelength or bursts from different connections share the wavelength, we propose a resource reservation and allocation algorithm. Our strategy allows resource dynamically allocated among the virtual connections over the optical network. By doing this, the number of backbone nodes and competition for wavelengths are reduced. So the algorithm is a promising way to minimize blocking and provide better wavelength capacity utilization. Consequently, the number of required optical devices is reduced and the network cost is decreased. Furthermore, our algorithm is distributed; it can give high degree of flexibility. The effectiveness of this scheme in improving the performance of network is demonstrated through simulations.

Homodyne crosstalk in multiwavelength optical cross-connects (OXC) is studied. The bit error rate (BER) and power penalty due to the incoherent and coherent crosstalk are derived for IM-DD transmission. The impact of the WDM wavelength number, same-source crosstalk number, the cross-connecting state of the OXC, the polarization angle difference between the crosstalk contribution and the signal on the crosstalk performance is discussed.

The symmetric directional coupler with optical rib waveguide is simulated using a novel three-dimensional beam propagation method (3D-BPM) based on the Galerkin method. The coupling ratio is as high as 99.4%. The matrix derived from the present method is small. Consequently, the calculation is efficient. A tangent-type function is applied to map the infinite region into a closed region. As a result, the artificial boundary conditions are eliminated.

A monolithic integrated photoreceiver for 1.55-micrometers wavelength fiber-optic receivers has been designed and fabricated with one amplifier stage, two stages of source follower and a feedback resistance structure. The optoelectronic integrated circuit (OEIC) receiver combines an InGaAs MSM photodetector with InP-based InA1As/InGaAs HEMT. The receiver demonstrates a transmitting bit rate of 2.5Gb/s with a transimpedance of 58(Omega) dB. While operating at 2.5Gbit/s, the chip consumes 160 MW at a single+5V supply voltage.

Forward error correction (FEC) is one of the newest technologies improving the performance of optical transmission systems. Out-of-band FEC providing high coding gain is the FEC type in common use, and RS (Reed-Solomon) coding capable of correcting both bursty errors and random errors is the most efficient coding used in the systems. In this paper, the error-correcting capability of RS codes with various levels of overhead is compared theoretically; the performance of optically amplified systems is analyzed by means of non-Gaussian approximation instead of traditional Gaussion approximation; based on the theory above, the system performance improved by FEC or Enhanced FEC (EFEC) is numerically simulated and discussed respectively with a view to the side-effects of out-of-band FEC due to increased channel bandwidth. Analyzing the performance of optical transmission system with FEC is not new, the contribution of the paper lies in its more precise approach*non-Gaussion approximation, furthermore the side-effects caused by out-of-band FEC are taken into account, by which the potential of FEC in increasing the capacity and improving the performance of optically amplified systems is illuminated more accurately.

A novel low-cost 1í+7 plastic optical fiber coupler using cylindrical mixing-rod is proposed. Comparing with conventional tapered mixing-rod plastic optical fiber 1í+7 coupler, the proposed coupler, which uses cylindrical POF as mixing-rod instead of tapered POF in order to save the high demanding POF tapering process, is much lower at cost and only a little deteriorate at crosstalk. The increased crosstalk and its power penalty are theoretically calculated showing that crosstalk lower than 20dB results in insignificant power penalty. The coupler was experimentally tested showing an excess loss of less than 2.5dB and uniformity less than 3.56dB.

A direct current voltage sensor based on all-fiber Mach- Zehnder interferometer is demonstrated, which utilizes electrostriction effect of Piezoelectric Translator. The character of voltage sensing is studies experimentally. Adopting the wavelength scale method, in the case of elimination of environmental perturbation, the wavelength changing range is 3.86nm when the voltage changes from -58v to 58v. The tuning sensitivity and the linear fitting are 0.033nm/v and 0.9985, respectively.

Refractive index profile is required to calculate waveguide properties. This profile can be reconstructed by analyzing its near field image. The measured near field image, which is obtained by using inverse propagation mode near field method, is processed by a computer image processing programme. The image processing procedures adopted in this work include background noise substraction, gamma correction, smoothing and filtering with neighborhood averaging filter. These procedures produced a parabolic refractive index profile. By fitting half of refractive index profile in x and y direction from fiber center using non linear least square regression technique, it is known that the index profile had a power factor, alpha equals 2.218958 in y direction and (alpha) equals 2.626216 in x direction. Fitting process is also derived for variety refractive index profile according to power-law profiles ((alpha) -profiles), with power factor, (alpha) equals 1,2,4, and 10 to the measured refractive index profile. The best fitted curve is determined by its minimum deviation.

A detailed study is carried out on four oxygen-rich silicon oxynitride samples as an as-deposited one and other three same ones annealed at 600 degree(s), 750 degree(s) and 900 degree(s) respectively by Infrared spectroscopy (IR) and X-photoelectron spectroscopy (XPS). It is shown that the as-deposited sample consists of configurations as SiN_x (xequals1,2,3,4), O_nSi$4--n)-NH (nequals0,1,2,3), Si-O₄, Si-OH, N-OH, SiN-O and SiNequalsO. With the annealing temperature rising, other configurations diminish or disappear and thus the microstructure mainly consists of O₃Si-NH and Si-O₄. As the temperature steps higher to 900 degree(s), most of H is released, leading to the appearance of a great amount of O₃SiN- with a N dangling bonding, thus a sharp increase in the inner stress, and the reappearance of SiN-O, SiNequalsO and SiN configurations helps to compensate the inner stress.

We propose a novel method of transform spectral measurement, based on the diffraction of light through the side of a waveguide fabricated in photorefractive crystal where a holographic grating is recorded by holography. The optical spectrum can be obtained by Fourier transform for the interference pattern, which is formed by lights diffracted from counter-propagating mode in the waveguide. Changing the periodic length of the holographic Bragg grating recorded in the waveguide can widen the range of measurable spectrum. This spectral measurement method is well suited as high- resolution wavelemeter, terminal network spectrum monitor and spectral measurement advice for fiber-grating sensor.

The advantages of multivalued logic in optical parallel computation need no introduction. There are lots of proposals, already reported,where tristate, quarternary state logic operations can be performed with optics. Here in this communication we report a completely new approach to implement quarternary state logic operations and their practical possibilities in optical computation.

We have studied experimentally the electro-optics properties of the slab waveguide induced by the electric poling. The thin film waveguide is made by a commercial polymer PA-11 and was poled by applying voltage between the botttom electrode and the top electrode. The poling voltage dominates the magnitude of E-O effect. In this work, I-V curves and electro-optic characteristics of the PA-11 films were in-situ measured during poling. In order to evaluate the molecular dipole alignment under the poling field, absorption spectra of this film was observed by the FTIR. Moreover, the static field analysis of the poling electrodes is performed to determine the optimum electrode geometry. Numerical evidence demonstrated that the distribution of poling field is function of electrode spacing and width. Thus these numerical results should be useful to establish a novel guideline for designing the poling electrode of poled polymer waveguide devices.

Characterization results of cladding layer for photonic integrated circuits are present. The silicon oxide films were deposited by various methods. The mechanical stress, depending upon the methods of film deposition, had been measured. TEOS silicon oxide exhibited large mechanical stress. The stress of polymer benzocyclobutene (BCB) was also measured. Its stress is only 29 MPa. The roughness of BCB surface is 1.18 nm. The mode profiles of planar waveguide were calculated.

By packaging fiber gratings with two different polymers mixed at the definite rate, the temperature sensitivity experiments of the grating packaging component have been studied. The experiments indicate that the grating component has fine linear temperature sensitivity in the normal temperature range between 20 degree(s)C and 80 degree(s)C, and has good temperature sensitivity in the high temperature range between 100 degree(s)C and 300 degree(s)C, which comes close to the temperature sensitivity of the bare fiber grating.

A new method using the genetic algorithm to design fiber Bragg grating filters is proposed. The filter is construct of cascaded uniform fiber Bragg gratings. The genetic algorithm is used to choose the parameters of the uniform fiber Bragg gratings. The numerical examples of synthesis of low pas filter, high pass filter, band pass filters, linear filter and gain flattening filter are given.

We start from Kukhtarav equations and Gauss's law which describe the photorefrective effect in a photorrefractive medium in which electroncs are the sole charge carries, plus the wave equation for the slowly varying amplitude of the optical field , In steady state and two dimensions the distributions of the nonlinear refractive index in a photorefective cystals under the conditions of supporting low intensity spatial solitons are studied theoretically. It is shown that steady state spatial bright solitons of TEM_n0(n=2,2,3...)modes and modulated TEM_n0 mode Gaussian waveform can form and induce planar array waveguides in photorefractive crystal.

A simpler method for the fabrication of multilayer porous silicon optical waveguides is studied in this paper. It is based on the dependence of porosity on illumination intensity during anodisation process. The influence of illumination intensity on porosity during preparing porous silicon was studied. The experimental results show that the porosity of porous silicon has a maximum value under certain illumination intensity. Porous silicon channel waveguides were obtained by controlling the illumination intensities and the anodisation time in anodisation time in anodisation process.

This paper presents the design and development of a bit rate adaptive 3R O/E/O transponder, which accomplishes full data rate and protocol transparency from 30Mb/s to 2.5Gb/s by signal processing in electric domain. This transponder makes use of chipsets that perform clock recovery in continual bit rate ranges, that is, software configuration and provision are achieved for continual bit rates. The measuring results presented in this paper show us that a good bit rate-adaptive capability and a good BER performance can be achieved, which indicates the commercial application is feasible. This paper also discusses the architecture extension and application of this transponder toward an intelligent photoelectronic gateway for the future application in wide area optical networking. Transition from research laboratory into the marketplace is also undertaken now.

Highly stable single wavelength pulse train was generated in a fiber ring laser by using a F-P semiconductor laser diode simultaneously as the modulator and the tunable filter. Compared with systems using M-Z interferometer modulator, this experimental setup need lower gain to produce stable mode-locked pulse due to the lower cavity loss. As a result, continuous wavelength tunable range up to 1nm was achieved by changing the LD temperature. And the frequency pulse with pulse-width 50ps was 2GHz.

A curvature sensor based on fiber Bragg grating (FBG) is demonstrated in this paper. Two FBGs are surface-bonded on opposite sides of a flexible beam to track the local curvature variation. The bending-induced strain causes opposite changes in their Bragg wavelengths. As a result, temperature-independent curvature measurement with sensitivity of 3.21nm/m^MIN1 is achieved by monitoring spacing between the two Bragg wavelengths. The experimental results agree well with the theoretical analysis.

A novel technique for fiber Bragg grating sensor is introduced. The sensor is successfully used to measure wavelength-shift induced to strain and temperature. The experiment results agree with the theory and indicate that the sensor has good linear response capacity and high intensity signal and signal to noise ratio.

Birefringence gratings induced by 532nm polarized laser in an azobenzene doped polymethyl methacrylate (PMMA) fiber and perform block were investigated. Significant photo-induced birefringence has been observed from the fiber. The maximum induced index change is about 3.1x10+MIN5) from this material. The induced birefringence was attributed to the nonlinear absorption at 532nm wavelength. It is found there is the threshold intensity of 0.29mW/cm². The birefringence decayed little by little when laser turned off, a certain amount of saturation was remained. The dynamics process of the birefringence was studied. This birefringent grating may apply in the polarization dispersion compensation of the fiber communication.

We design a Raman Fiber Amplifier(RFA) pumped by 1435nm and 1470nm wavelength lasers.Heavy GeO₂-doped optical fibers are adopted as gain media for the more symmetrical gain curve.The amplifier is designed to be distributed in two fibers to avoid intense power transferring between the two pump lasers when propagating in single fiber.Considering the spontaneous Raman scattering and the fiber loss,the numerical calculation is made to optimize the design of the RFA to get wide bandwidth and flat gain.

The paper focuses on analyzing the effects and principles of the capacitance and inductance peaking technology in 10Gb/s HEMT external modulator driver module. Based on the accurate microwave monolithic integrate circuit (MMIC) inductance equivalent circuit model, the effect of inductive compensation to the gain and bandwidth of driver module is discussed. By using the technology of gate inductive peaking and drain inductive peaking, the fT of HEMT device used in driver module reduce evidently from 54GHz to 35GHz.

On the basis of the arrayed waveguide grating (AWG) multiplexer theory, some important parameters are optimized for the structural design of a polymer AWG multiplexer around the central wavelength of 1.55micrometers with the wavelength spacing of 1.6nm. These parameters include the thickness and width of the guide core, mode effective refraction indicees and group refractive index. Pitch of adjacent waveguides, diffraction order, path length difference of adjacent arrayed waveguides, focal length of slab waveguides, free spectral range, number of input/output waveguides, and that of arrayed waveguides.

A data decision IC is designed for STM-16 SDH-systems. A differential high-speed master-slave DFF is used for the decision function. Wide-band high-gain amplifiers are used for input and output data buffers to obtain high sensitivity and sufficient drive capability. The chip was realized in a 0.35-μm CMOS foundry technology. The chip size is 0.7x0.8mm².The supply voltage is 5 V and the current is 50mA. A working data rate of higher than 3.5Gb/s has been measured. The sensitivity is as low as 10~20mV.

The design of optical array generator is based on the scalar diffraction theory. Optical array diffraction intensity is the same for all diffraction levels. Optical array generator can be modulated by either the amplitude or phase profile, however, phase array generator is done through ion etching. The design and fabrication of highly efficient optical array generator is studied, one and two dimensional optical array generator is designed, which generate 16, 32,64, 256, 1024, 4096 uniform optical arrays separately. The optical array generator has been used in optical pattern recognition and multi-channel imaging, and the experimental results are presented.

We recently developed an acousto-optic (AO) device that based on one such all-fiber component, and one single-mode fused taper null coupler. It has been successfully demonstrated as an optical switch at wavelength of 1.55micrometers . According to the coupled mode theory, power distribution of the null coupler with the acoustic-wave is formulated for general case. Excess loss of 0.1dB and the schematic graph of throughput and coupled power are obtained experimentally. The driven power requirement is very small.