In this paper, the coupling characteristics of a dielectric directional coupler consisting of two parallel rectangular waveguides are analysed. We make use of variatonal analaysis to obtain the coupling length. It is shown that the presented technique is much more accurate than the widely used Marcatili s method as well ag pertrubation method. By means of this method, coupling length can be easily calculated with high accuracy, and it can be extended to the analysis of other devices n integrated optics.

The effect of temporally partial co herent on noise performance of a whit light optical signal processor is presented. The output signal-to-noise rate (SNR) is used a9 a means of measuring noise performance of the proposed whitelight processing system. The noise sources considered are the grain-noise and phase-noise at any plane in the system. The result shows that the set-up noise can be restrained and the output SNR can be improved considerably by using broad band temporally partial coherent illumination.

In this paper, we propose three new basic apertures in rotating aperture method: rectangle-located-aperture and parallelogram-located-aperture and right-triangle-located-aperture. Theoretical analysis and experimental demonstration are presented. By using these new apertures, the utilization ratio of information of a specklegrain is increased, the intensity distribution of diffraction halo becomes more reasonable and the N/S ratio is enhanced, so the speckle fringes are clearer and the experimental errors are less.

The light field distribution in Fourier filtering plane of speckle shearing photography is discussed in this paper. The conclusion is that the areas of light field are limited by the boundaries of autocorrelation and intercorrelation of the aperture functions. Theoretical analysis on optimum aperture functions, which could improve effects of filtering and the quality of fringe pattern is also made. Experimental resulta accord with the theoretical analysis.

This paper presents a new simple method to determine and divide the fringe orders in speckle method. Therefore, the displacements are measured and the accuracy is improved. It also can be used with computer for automatical analysis.

A 150ns 150mJ laser output was obtained from a novel two channel discharge pumped exoimer laser by folding two optical path to form a longer laser cavity (2 m) and elongating discharge durations appropriately.

Bate equations of Gaussian shape pulse modulated semicouductor lasers are solved by Runge-Kutta method, and the results are analysed. The formulae for calculating the delay time, pulse width of laser pulse and maxiimum bit-rate of Gaussian shape pulse modulation are derived. The experimental results of modulation pattern effects are given.

The paper describes our dynamic monitoring system for fused fiber couple manufacture. By using the time delay technique the system not only can indicate accurately by digital display the static power-splitting ratio of fiber coupler, but also can control the change of power-splitting ratio during process of fiber coupler manufacture, consequently increases the finished productivity of fiber coupler.

The angular and frequency characteristics of deflection gratings on planar optical waveguide are discussed through evaluting the deflection efficiencies R obtained from the coupled mode equation. The analysis shows that these propertie in principle depend on the product | K | · L of the length L and the coupling coefficient |K| between incident and deflecting waves, rather than | K | or L individually.

An expanding method for solving SRS wave equation with Gaussian-Hermite modes is presented. An analytical solution is derived neglecting the condition of pump depletion and used for discussion of threshold condition and wave front reproduction.

In this paper a lateral shearing interferometer using double fooal-length wave-zone-plate (DFWZP) is proposed. The plate can easily be produced holographioally as shearing element. This interferometer is very suitable for the measurement of converging wavefront. It not only retains the advantages of the Ronchi grating testing method but can also obtain the interferograms of good contrast. It provides Variable shearing and does not require the replacement of DFWZP. This interferometer can obtain shearing shearing interferograms in any desired direction by translating the DFWZP in the DFWZP plane. Hence it can be used to test rotationally nonsymmetrio wavefronts. The fabricating and adjusting derivations of the DFWZP is one of the souzoes of measuring errors. The quality of the DFWZP oan be tested with the star point method.

On the basis of defocus and non-coaxality induced by framing lenses in an approximate circle, the precision formulae for calculating the defoous of image points in the film in another approximate circle have been deduced in this paper. Errors caused by the traditional calculating method have been eliminated and more reliable data can been obtained for the evaluation of the image quality in a rotating mirror framing camera.

We use the Monte-Carlo method to calculate the intensities of transmission and reflection of a collimated light beam scattered from randomly distributed particles in thin layer. The results obtained are compared with those calculated by the transport theory of diffusion approximation. When the scattering is nearly isotropic, both of the results agree well. When scattering becomes anisotropio, the results from Monte-Carlo method are reasonable, while the theory of isotropio scattering approximation becomes invalid.

General expressions of Goos-Hanchen shift for both s and p polarizations from absorbing medium has been derived in this paper. Let the extinction coefficient be equal to zero, they will be simplified to the formulae[1] given by M. McGuirk and C. K. Carniglia, which are only fit for non-absorbing medium. The shift from absorbing medium occurs at any incident angle except zero angle. On Gallium surface, Goos-Hanchen shift may have several wavelengths.

The first observation of eleotro-optio induced waveguide and dark spot phenomena in SBN:60 is reported in this paper and a new eleotrooptio modulator with lower driven voltage, high modulation factor of amplitude modulation is demostrated.

The laser damage of silicon in silicon photoeleotronic has been investigated with a 1.06μm laser. Laser pulse duration is 50ps and energy is 20mJ/pulse. Calculations show that the damage occurs at the silicon surface and depend on pulse duration time, laser energy flux and manner of the laser irradiation. The experimental result is in agreement with the theoretical analysis.

Brsed on the wave theory of optics, the affect caused by the phase error in Fresnel near-field diffraction equation is analysed. Taking single slit as an example, the relationship between phase error and resulting accuracy is given. Prom calculating of the focal plane intensity distribution on Linear Presnel Zone Plate, the results of using Fresnel diffraction equation is stated when the phase error requirement is not satisfied. Some facts affecting the focal plane intensity distribution of LFZP are given.

We have observed several new intensive fluorescence spectra in a Na spectral lamp working at normal conditions irradiated by nonresonant laser. The possible mechanism is analysed.