Fiber optical ring is the core parts of the interferometric fiber optical gyro. The external circumstance such as temperature and stress can induce nonreciprocal phase noise, which restricts the developing of high precision gyro. The quadrupolar ring's temperature field is studied numerically by finite difference method, its null drift is analyzed at given temperature circumitance. The cross winding technique is proposed, which is good for weakening the null drift induced by temperature.

A new explanation of the intensity-dependent subpulse structure of linearly polarized picosecond optical pulses in a single-mode optical fiber is presented by means of the coupled wave equations between two polarization components, taking into account both the intrinsic linear birefringence and nonlinear birefringence. The results of simulation shows good agreement with the experimental results.

statistical optimum design method suitable for temperature-insensitive waveguide coupler is proposed. Using the method, 120 nm waveband fluorinated polyimide waveguide 3 dB coupler is designed with the optimization of the temperature fluctuation. The design result is verified by the 3D-BPM simulation, and shows that the coupling ratio of (0.500±0.007) in the waveband of 1490～1610 nm and temperature region of -10～40 ℃ is realized. The measuring method for refractive index dependence on temperature and for dispersion characteristic of the fluorinated polyimide film is also reported

The application of CFDTD (cylindrical finite-difference time-domain) algorithm in the analysis of weak-guiding optical fiber and other types of fibers is discussed. Especially, the setting of the absorbing boundary condition and the calculation error are presented, improvement way is proposed. Further more, this method is applied to the calculation of propagation characters of optical fiber and the photonic crystal fiber, some useful results are given.

The residual thermal stress distribution is evaluated in the silicon-based silica optical waveguide with finite element method and the stress birefringence is obtained. The influence of stress on polarization is analyzed. It is concluded that birefringence is induced mainly by the different expansion coefficient between the substrate and glass layers. The birefringence-free planar optical waveguide can be obtained by increasing the level of dopants to match the thermal expansion coefficient of glass layers to that of the substrate.

A novel design for DWDM interface device interleaver is proposed and discussed, which is composed by 3×2 Match-Zehnder interferometer with thin film Gires-Tournois interferometer type optical all pass filter (GTI-OAPF) inserted. Influences on its transmission characteristics by such factors as the reflection coefficient of the partial reflector in the GTI-OAPF, detuning of the coupling angles of the directional fiber couplers from ideal values, chromatic dispersion and various losses are numerically analyzed in detail. At last, a novel six-port bi-directional interleaver, which will be used in bi-directional multi-function photonic module and bi-directional WDM transmission system is proposed as well.

Conventional formula for a Gaussian beam propagating in a homogeneous slab waveguide can be derived by solving the Helmoholtz equation with the paraxial approximation. Based on the Kirchhoff diffraction theory, a more accurate formula is derived. The quantitative error of the conventional formula is analyzed and a modification is given to improve the accuracy. The accuracy of the modified formula is verified by a numerical simulation with finite difference-beam propagation method (FD-BPM). The modified formula can be used to simplify the design and simulation for integrated photonic devices such as arrayed waveguide grating (AWG) and etched diffraction grating (EDG).

A novel approach to the super-resolution pits readout--super-resolution reflective film technique was put forward, and its principle was analyzed in detail. By using Sb as the super-resolution reflective layer and the SiN as dielectric layer, the super-resolution pits with a diameter of 380 nm were read out by the readout optics system (the laser wavelength is 632.8 nm and numerical aperture is 0.40). The influence of the Sb thin film thickness on the readout signal was investigated, the results showed that the optimum Sb thin film thickness is 28～30 nm, and the maximum signal-noise ratio is 38～40 dB.

An experimental study on the photothermal excitation of bi-layered silicon microresonator is presented. Two methods are used to test the microresonators in the air environment, including the photothermal excitation and electrical sensing method. Corresponding vibration waves of the first three modes are observed in the experiments successfully. By using single optical source, a new method is presented to realize the photothermal excitation and optical sensing at the same time which is more suitable for further application than the traditional two optical sources system.

The localization performance of a new amplitude cancellation localization scheme (interchange amplitude cancellation localization scheme) under non ideal case according with actual condition is analyzed using analytical model, especialy the performance when the resolution and sensitivity of the detection system is limited, and the interchange between two sources is not complete. The effects of the parameters of the heterogenous object on the localization performance of the system using the new scheme are also discussed. The results show that the method can reduce the effects of the relative amplitude and phase between two sources on the system, obviously improve the localization precision, and detect the heterogeneity with smaller size, deeper and smaller absorption coefficient.

new nonlinear weighted average multidirectional morphological filtering algorithm is proposed, which is used in suppressing speckle noise. The algorithm, otheralgorithm proposed by us, wavelet soft thresholding algorithm and Lee′s filter are applied for suppressing speckle noise in the Impulse Coherent Laser Radar Images, and the their results are compared. The conclusion proved the improvement of the proposed algorithm in suppressing speckle noise under the condition of preserving edges of the image

The illumination methods related closely to detect random defects on strongly reflective and complex surfaces with CCD detection are discussed. A concept of defect expressivity is developed and the dependency of image quality on luminance is illustrated in the condition of scattered light. Based on the comparisons between parallel light and uniform scattered light, it is concludes that uniform scattered light is much better than parallel light in reducing the mirror reflection and good at revealing the various surface defects. The design principles under those particular conditions are presented.

Based on the dipole-self-consistent field theory the influence of polarization of the incident light on the imaging quality of reflection mode SNOM is simulately calculated such as the system resolution and the image quality, and the theoretical explanation is given. The analysis result shows that the imaging quality greatly depends on the polarization of incident light at the probe tip of the microscope. In the near field imaging, the system resolution is better when the incident light is polarized vertically to the surface (via z-axis polarized) than that when it is horizontally polarized. When the incident light is x-axis polarized, the imaging achieved by scanning the object can reverse locally in contrast.

After considering the fact that the holes contained in spatial filter may also serve to isolate the ghosts in different areas, a optical matrix method for locating the nearaxial ghosts in high power laser systems is proposed. Practical criterions of distinguish real and virtual ghosts are put forward. Program designed can be used to calculate arbitrary order ghosts of a laser amplifier system.

Waveguide dispersion characteristics of two kinds of triple-cladding single-mode fibers named WⅠ and WⅡ is discussed. According to authors′ research, it is concluded that the range of the zero dispersion point of the WⅠ-and WⅡ-type single-mode fibers is obviously larger than that of the conventional W-type single-mode fibers under the same condition. The influences of the geometric parameters P, Q and optical parameters R 1, R 2 on the waveguide dispersion and cutoff frequency of low order modes for WⅠ-and WⅡ-type fibers are analyzed. The result provides a significant reference for the designs of new types of dispersion-flattened fiber, dispersion-shifted fiber and passive optical devices. The method to calculate waveguide dispersion can be applied to multi-cladding fibers.

By using the CCD test system of gain distribution uniformty, the gain distribution uniformty of a new high power solid-state laser multi-segment-amplifier pumped by flashlamp was measured experimentally. Under the condition of charge voltage of 23 kV and pumping energy density of 11 J/cm3, the small signal gain coefficient distribution uniformty in full aperture of 4×2×3 multi-segment-amplifier is 1.10∶1.

Through the research on temporary pulse-shaping technology, a new type of laser pulse-shaping system is developed for the future high-power laser facility. In this pulse-shaping system, the 1.053 μm proton-exchange waveguide modulator is used. By using this shaping system, the square laser pulse is obtained and the fluctuation is less than 10%.

Based on the concept and the treating techniques for photonic crystals, the characteristics of the forbidden band structures in one dimensional reflection hologram are analyzed. It is treated in the consideration of the reconstruction beam being incident to reflection hologram at different incident angles. The analysis shows that, for oblique incidence, the structures of forbidden band in hologram are slanted. For normal incidence, the structures of forbidden band in hologram are unslanted, and it is the special case of oblique incidence.

The finite-difference time-domain (FDTD) method is developed for the study of transmission characteristics of 2-D photonic crystals. Transmitted power of TM mode and TE mode of 2-D square lattice photonic crystals are given. Based on scaling properties of photonic crystals, the photonic crystal behaving in the electromagnetic zones is fabricated and experimentation is designed. The theoretical results confirmed the experimental results. It is shown that the light with a certain frequency and incident direction can not propagate in the photonic crystal.

Pyrryl fulgide is a new type of organic photochromic material which can be used in EDRAW (Erase Direct Read After Write) optical memory. The absorption spectra of the bistability of the pyrryl fulgide are measured. The maximum absorption of the colored state is centered at 635 nm,the peak absorption of the bleached state is at 385nm. With the thermal stable states, optical images are steadily recorded on the pyrryl fulgide/PMMA film. The contrast of the recorded images is high enough, so it can be easily read out directly by a usual camera. The images on the film have been kept for six months without any degeneration. The storage period is estimated to be as years in dark at room temperature.

ZnSe films with thickness from 0.045μm to 1.4μm were grown by MBE on (100) GaAs substrates and characterized by room temperature Raman scattering. The relationship between the coherence length L and the qualities of ZnSe films was analyzed from the line shapes of the first-order longitudinal-optical phonon Raman scattering quantitatively. The shift asymmetry of the LO phonon peak was investigated in detail. The results show the quality of ZnSe film is gradually degenerated with the decrease of the film thickness. This is attributed to the lattice misfit-induced imperfection in epitaxy layers. This result coincides with the experimental one.

A complete method based on perspective imaging model is established to design catadioptric omnidirectional system with undistorted imaging for horizontal scene. The approximate perspective imaging characteristics about this imaging system is analyzed. A mirror has been designed, and a catadioptric omnidirectional system with undistorted imaging for horizontal scene has been developed. The image taken by this catadioptric omnidirectional system is compared with the real image taken by hyperboloidal omnidirectional system and its perspective omnidirectional image.

PV HgCdTe infrared detectors were irradiated by continuous-wave 1.319 μm laser light of various intensities. A series of output of detector No.1, No.2 under various laser intesities were shown. Some new phenomena, chaos and zero-output, were observed. The results are quite different from theoretical expectations. It is of great interest for future research on PV HgCdTe. A qualitative explanation is given.

According to the electro-optic effect of liquid crystal and the theory of Lyot filter, the tunable liquid crystal filter is designed. Its feasibility is tested theoretically and experimentally. In order to overcome its disadvantages in infrared band, Fabry-Pérot tunable liquid crystal filter is designed and its analogue is given. It is proved that the Fabry-Pérot tunable liquid crystal filter has great tuning range and narrow band.

The fluorescent spectra of the phosphors CaS∶Ag prepared rapidly by microwave radiation method are studied. The XRD analysis shows that the structure of the phosphors belongs to cubic system. The SEM photographs show that all the CaS∶Ag phosphors possess spherical shapes, but the effect of different fluxes and silver concentrations on crystal size and distribution is different, they are nano-scale (7～100 nm) and submicron-scale (125～300 nm) crystallines. The excitation and emission spectra of the phosphors CaS∶Ag are measured and explained. In emission spectra, three peaks located at 372 nm, 450 nm and 577 nm have been observed, respectively. With different fluxes and with different silver concentrations, the emission spectra of CaS∶Ag phosphors change complicatedly. The peak of 372 nm is produced by AYg′ Ca-V 2 S centers. The peak of 450 nm migrates to shorter wavelength with the increase of silver concentrations. It is caused by interstitial Ag ions. The peak of 577 nm is quenched by increase of silvr concentrations. It is caused by interstitial Ag+ ions. The peak 577 nm is quenched by increase of silver concentrations. It is produced by substitutive Ag+ ions and fundamental emission of CaS. In addition, the good distribution of crystal attributes to the increase of Iblue/Iyellow. During the preparation of CaS:Ag+ in microwave field, three colors powders have been obtained. They are white powder, light gray and brown. The quantitative analysis based on their XRD experimental data shows that the microwave reaction mechanism is that the diffusions of ions in the microwave field are enhanced.

The initial observation of CO 2 absorption at 1.57 μm near-infrared tunable diode laser wavelength modulation spectroscopy (WMS) combined with second harmonic detection reported. A minimum detectable absorption of 8.6×10 -5 (signal-noise-ratio is 2) was achieved, it corresponds to 500×10 -6 detection sensitivity.

By investigating a bilayer gastrointestinal normal tissue (including mucosa and submucosa layers) and a cancerous tissue model (including adenoma and submucosa layers), the laser-induced autofluorescence (LIAF) spectra by Monte-Carlo simulation are reconstructed. The good correlation between the reconstructed spectra and experimental spectra suggested that Monte-Carlo simulation can accurately describe the generation and transportation of fluorescence in tissue and therefore can detect cancerous tissue by revealing the real biophysical and biochemical information of tissue.