The reason that multimode waveguide of total internal reflection (TIR) based Y-branch switch has less cross-talk and less loss are analyzed by utilizing waveguide theory. A physical model of TIR is given and an approximate calculation method of improved TIR Y-branch switch is obtained. Simulation shows that the cross-talk and loss of the multimode waveguide of TIR Y-branch switch decrease by 15.5 dB and 0.65 dB respectively.

The band-pass-filtering characteristics of series-coupled double-ring optical microresonators are studied. Based on the transfer function, the related bandwidth formula of the passing band is derived. The influences the into-/out-of-ring and ring-to-ring coupling coefficients on the filtering characteristics are analyzed. The structure of the passing band is calculated and emphasized. The influence of the optical loss in the microring is also analyzed.

Based on dynamic demodulation technique, a method of strain measurement using two fiber Bragg gratings is reported. The shift of reflective wavelength of one FBG under external strain is translated into a change in time interval of the optical pulse from another FBG drived by a PZT plate. Experiment demonstrates that the measurement accuracy can reach 2.5 mN with the range of 0～40 N.

A novel screwdriver-like shaping system for the usage of coupling between high-power laser diode and multimode fiber (MMF) is presented. The effect of cutting angle, cutting depth and coupling distance between laser diode and screwdriver-like fiber on the coupling efficiency is analyzed in detail. A method for coupling efficiency calculating is provided. An example of efficiency calculating is provided, and optimized parameters that can work well with the screwdriver-like coupling system are obtained.

PMD has been the major limiting factor for long haul high bitrate optical fiber transmission. The relationship between 1st order PMD and optical signal DOP (degree of polarization) of PRBS NRZ/RZ is discussed in theory, and the impacts of different input states of polarization and higher-order PMD on signal DOP of NRZ/RZ are analyzed by numerical simulations. Then, Monte-Carlo simulations are performed with all order PMD model on the statistics of PMD compensator, which uses signal DOP as the feedback control signal in the 10 Gbit/s NRZ optical transmission system. The statistical simulation results indicate that the compensation probability for the signal eye-diagrams can reach 99.99% when the average DGD of the link is below 43 ps.

The switch window of demultiplexer using an electroabsorption modulator (EAM) is simulated and analyzed theoretically combined with the channel crosstalk and intensity fluctuations (synchronization deviation and time jitter). Results show that the characteristic of switch window (extinction ratio and window width) can be used as demultiplexer of 4×10 Gb/s; under small DC reverse bias, the tradeoff between the channel crosstalk and the optical transmissivity of the target signal has to be considered carefully; under large DC reverse bias, the maximum RF amplitude can lead to minimum bit error rate (BER).

In Fourier transform profilometry (FTP), when zero component extends to fundamental component, it will influence measuring range and measuring precision, even makes the correct three-dimensional surface impossible. π phase shifting technique is usually used to eliminate the zero component. But this needs adding phase shifting device in measurement system and capturing two fringe patterns with π phase difference each other. Now a novel method is proposed, in which a bi-color fringe pattern is projected onto the object and the deformed color fringe pattern is captured by color digital camera. Two separate fringe patterns with π phase difference are extracted and used to eliminate the zero component. The method not only can eliminate zero frequency overlapping fundamental component using only one fringe pattern, but also simplify the experimental setup because of no need of phase-shift device.

A three-dimensional volumetric display system utilizing a rotating panel is described. The LEDs are arranged in a matrix configuration on the panel. They can be addressed by control circuit to create a sequence of two-dimensional image information at a predefined interval. These discrete images will be perceived and interpreted as an integrated three-dimensional image due to eye persistence. The system can provide 49152 voxels in a cylinder display space with a diameter of 144 mm and a height of 110 mm. The three-dimensional image displayed provides viewers with true depth cues, binocular parallax, accommodation and convergence, etc., and can be observed from any directions horizontally without the need for any special viewing aids. The structure, principle of displaying method and the volumetric information encoding are discussed. Moreover, the relationship between quality of display, optimization of selection of voxels and initial image information displayed are analyzed in detail.

A new method for three-dimensional multispectral image data compression based on an improved Karhunen-Loève Transformation (K-LT)/wavelet transformation spectral feature coding vector quantification (WSFCVQ) is proposed. Three-dimensional Karhunen-Loève transformation/wavelet transformation/spectral feature coding vector quantification (SFCVQ) implement three-dimensional compression for three-dimensional multispectral image data with two-dimensional set partition embedded block (SPECK) and one-dimensional spectral feature vector quantification (SFVQ) coding, applying Karhunen-Loève transformation to exploit the spectral correlation in multispectral image data and using two-dimensional wavelet transformation (WT) to remove the spatial redundancy in the multispectral image data, and a high compression performance is got as well. Experimental results show: if Karhunen-Loève transformation/wavelet transformation/wavelet spectral feature coding vector quantification (WSFCVQ) method are compared with the method of Karhunen-Loeve transformation/wavelet transformation/improvement BiBlock zero tree coding (IBBZTC) and the method of Karhunen-Loeve transformation/wavelet transformation/fast speed vector quantification (FSVQ), the peak signal to noise ratio (PSNR) is enhanced by over 2 dB and 1 dB, the compression speed increased by 1.5 and 8 times respectively, and the total compression performance is greatly improved.

The relationship between parameters of airborne laser bathymetry (ALB) and its maximum penetration depth is discussed. The minimum detectable signal-to-noise ratio is taken as the criteria of choosing parameter. The performance of ALB in daytime and nighttime is evaluated, and the relationship between maximum penetration depth and transited peak power, receiver aperture, angle of field-view, and spectral bandwidth is demonstrated. The ALB system with the chosen parameters has a penetrability of 49 m in daytime and 65 m in nighttime. It is matched the requirement of costal charting and rack detection.

In order to settle the influence of measuring results of particles with its shape-variety, the shape-influence factor of arbitrary particles in Gauss scattering field is discussed based on the half-ellipse model, the mathematic relation between the shape-influence factor and size and shape of particles is rebuilt, and the distribution of numerical-solution of the influence factor is obtained. The analytical formula solution of the influence factor is fitted in Gauss scattering field based on the studying of the dynamical characteristics of it. Then the perturbation equation about the probability distribution characterized-function of arbitrary particles is improved. It shows that this method is very useful for partides with large diameter in the shape-modifying.

The behavior of self-Q-switched diode pumped solid-state laser (DPSSL) has been investigated by numerical simulation by using the rate equations of solid-state lasers. Analytical formulas for the peak power, pulse energy, pulse width, energy extraction efficiency, repetition rate and average output power are derived. The optimal length of self-Q-switch crystal with minimized threshold pump power and the optimal length with maximized light-light efficiency are obtained.

A tunable diode laser is used in high-resolution spectroscopy, laser cooling of atoms, time standards, and coherent optical communications. It has a narrow linewidth, single frequency, and the wavelength is tunable. But its continuous tuning range is restricted by the mode-hop. The analysis on mode-hop suppression of the Littrow configuration and Littman configuration lasers and its continuous tuning range are presented.

The correlation coefficient of two wavefronts is proposed to describe and estimate the adding result of low-frequency phase aberration. Both the simulation and the experiment of low-frequency phase error adding propagation prove that the correction coefficient can efficiently be used to estimate the result of phase addition. Based on the result, a new kind of phase correcting methodphase self-correcting method is put forward, to properly choose and set the disk amplifiers in the high-power solid-state laser facility. The model to carry out the self-correcting method in high-power laser system is given.

Based on the angular spectrum theory, the principle of hole grating for sampling beam and attenuating power of high-energy laser (HEL), and the detailed structure design of a large aperture beam wave-front sampler are described. The numerical calculation and experimental results of far-field optical spot of the transmitted beam produced by the sampler are given. The results show that the beam wave-front sampler can attenuate power of HEL with little errors.

Photonic crystal coupling waveguide is developed when line defects are introduced into photonic crystals. The finite-difference time-domain (FDTD) method is applied for analyzing the waveguide coupling of 2-D square lattice photonic crystals. Transmitivity at exits of photonic crystal waveguide with different coupling length is given. Results indicate that photonic crystal waveguide coupling follows general regulation of conventional dielectric waveguide coupling. Further studies show that coupling coefficient of the photonic crystal waveguide directional coupler is different, coupling coefficient is linear with the corresponding frequency.

A 120 fs femtosecond pulse laser with wavelength of 800 nm was applied to irradiate YAG crystals grown by Czochralski (CZ) and temperature gradient technique (TGT) methods. Absorption spectra and EPR have been measured. The results show that Fe 3+ ions have been changed to Fe 2+ ions in CZ grown YAG crystals and F + centers formed after irradiation. Anti-irradiation ability of YAG grown by TGT method is better than CZ sample.

The main factors influencing the emitting characteristics of longtime afterglowing pigments are briefly discussed. The essential requirements for measuring the emitting characters are introduced. A new apparatus satisfied for the measurement of longtime afterlowing pigments is developed. It uses D 65 simulator as the stimulating source and uses auto-range photometer to measure luminance of longtime afterglowing pigments. The light from stimulating source to the pigment sample and the emitting light from the pigment sample to the photometer are transmitted by optical fibres. The stimulating light is controlled by an electric shutter which is coupled between the two optical fibres. The apparatus operated by a computer. It would be specially mentioned that the apparatus can be operated under the normal lighting condition. The measurements shows design of the apparatus is very ingenious and practical.

A new and simple gated photon counting system is described for the recovery of optical parameters in diffusive media. Compared with the traditional gated photon counting technique, the system is based on a 60 ns width-sliding gate that enables reconstruction of the photon decay curve at 200 ps time resolution, which is detected when a light pulse is impinged on the diffusive media. Patterson-Chance method allows the optical parameters of the medium under investigation to be retrieved quickly and accurately. Experimental results on a phantom modeling breast tissue demonstrate the feasibility of the technique. Good agreement with complicated time-correlated single photon counting technique plus curve-fitting method was achieved leading to less than 10% of miss-estimation on the optical parameters.

The temperature calibration has an important impact on the temperature accuracy, which is one of the two key performance parameters of distributed fiber optic temperature sensing systems. The physical essentials of temperature calibration is revealed and its effect on system temperature accuracy is analyzed. Some considerations and suggestions for practical temperature calibration design have been proposed.

The bright spatial solitons in logarithmically nonlinear electric media is studied. It is showed that the bright solitons are possible in corresponding nonlinear media. The spatial width for bright solitons is analyzed. It is revealed that the variation of the beam width is inversely proportional to the peak power of the source: beam width dramatically decreases with increasing the power when the peak power is much lower, exhibiting the good nonlinear effects in such case; The variation of beam width is slow and further constant, exhibiting the saturable propterties for logarithmically nonlinear electric media, when the peak power continuously increases.

A new method is used to measure the photorefractive index change Δn s (at saturation), the nonlinear absorption coefficient α and the photoconductivity σ ph at different input light intensity I simultaneously. The preliminary explanation for the experimental results is given.

A kind of method is introduced for inspecting the large aperture optics using a small aperture interferometer. The resolving process of the stitching parameter is discussed based on the statistic method. Furthermore the regressive analyzing method has been used in discussing the stitching accuracy. The experiment and the calculation example are given.

A phase unwrapping algorithm based on the solution of discrete Poisson equation is presented to retrieve the true phase of the object from wrapped phase. Algorithm model is constructed aiming at phase discontinuous and jumping caused by oddity points in interference pattern. Discrete cosine transform (DCT) is introduced to solve discrete Poisson equation which has Neumann boundary condition. Phase unwrapping results are obtained under least-squares method meaning. In comparison with the traditional algorithm, this method can effectively remove the discontinuous influence of shadow, blind spots, holes and noises, remove order jumping and wire drawing and resume true phase at the same time. Preferable experimental results are obtained in phase-shifting interference measurement.

Using atmospheric transmission model softwave Lowtran 7, the solar, atmospheric, sky and earth background radiation from 4 to 8 μm are calculated. According to the relationship between optical scattering theories on rough surface and bidirectional reflectance distribution function, the scattering of visible light from a spatial object is calculated. Based on the theories of heat transmission and background radiation, the surface thermal balance equation of spatical object is established according to the law of conservation of energy. Take balloon as an example, dependence of the temperature and radiation power on time, height and geographic location is calculated. The general law of infrared radiation characteristic of spatial object is obtained.

It is difficult to use the back testing method to test the large aperture asphere component made with special material such as the SiC. To solve this problem, the CGH for the convex surface testing is discussed and the practical optical parameters are given. The sample is a convex surface with the aperture of 100 mm, the obtained result indicates the possibility of the binary optics used in the convex surface testing.

The evolutions of quantum information for atoms, field and system in Kerr medium and Raman interaction are discussed. The effects of intensity of light, detuning parameters and Kerr coefficients on the fidelity are studied. It is shown that the evolutions of fidelity exhibit oscillations with equi-amplitude and perfect periodicity if the frequency of Rabi oscillation is the linear function of the photon number. Increasing the intensity of light will decrease the fidelity, and increasing the detuning parameters will improve the fidelity. Kerr coefficient affects the fidelity slightly and irregularly. The fidelity oscillates with equi-amplitude and perfect periodicity in the case of Δ=0, χ=0.5g and Raman interaction for degenerate levels.