With given material and profile type of the fiber, its isodispersion-coefficient distribution in the structure parameter plane can be drawn. By using such graph, the core diameter and relative core-cladding index difference are selected to meet the following demands: at the operating wavelength, zero dispersion coefficient is required; and from the predetermined dispersion tolerance (e.g., ±3ps/km·nm) the best acceptable structural tolerance is determined.

Based on the model of a four-layer dielectric slab wave-guide, the eigenvalue equation of a bent asymmetric slab wave-guide is derived from Maxwell s electromagnetic theory. The bending loss formula is then obtained with the change in propagation constant taken into consideration by perturbation method. Numerical calculations indicate that the formula is very accurate.

The transmission characteristics of the radiation from a UV XeCl excimer lager through fused quartz fibers have been investigated. The laser beam transmitted via optical fiber was used to trigger a spark gap. Experimental results show that the triggering jitter is less than 3ns. With use of two fibers, the same laser was used to trigger two spark gaps synchronously.

After making analysis of Rayleigh noise characteristics in an optical fiber gyroscope, we developed a new method to suppress the noise. Theoretically, we found that with this method the Eayleigh noise can be suppressed by a factor of |Jo(φm)|, here J0(x) is the zeroth-order Bessel function and φm the modulation amplitude. Therefore, with a proper modulation the noise can be reduce to zero. This new method is simpler and more effective than that using band-pass noise phase modulation.

The method to controll aotocorrelation intensity and related discrimination competence for a matched spacial filter by using two weights, EB (bias exposure) and f*(n) special frequency band), is discussed. Furthermore, application of this method is proposed for the synthesis of same-reference-beam noncoherent multiple matched spacial filters (SRNMF). Effects of the two weights on the autocorrelation intensity (IRt) and related disorimination competence (Cd) for the SRNMF are analyzed in detail. A formula is derived for estimating the optimized range of the exposure time (T). Experimental results are used to construct a curve of IRf vs. T, as well as curves for various fn(n) to show the relationships between and Ν and between Od and Ν· Where Ν is the overlay number of SRNMF.

The holographic and grating interferometric techniques for imaging through fog are reviewed. The holographic filtering technique for imaging through fog presented here can increase diffraction efficiencies of holograms and SNR of corresponding holographic replicas. We have also considered the situation when the object wave and reference wave both penetrate fog and the situation when the input object is reflective. Corresponding experimental results are presented.

Thermally insensitive resonators for multimode operation are investigatod theoretically by using the ABCD-law and. g*-, g -parameter equivalont resonators. Experiments on a Nd-glass laser have borne out the theoretical results.

A new-type rapid oscillation and self-mode-locking phenomenon in a high-gain laser is reported. Its mechanism ig due to the spacial modulation of the population inversion, this modulation will in turn cause an intensity modulation in the time domain. The oscillation frequency equals to the longitudinal mode interval c/2l.

We report the tuning characteristics of 16 μm OW PbSnSe diode lasers. We have measured CO2 absorption spectra near 618cm-1, 623cm-1, 634cm-1 and 667cm-1 as well as N2O absorption spectra near 618cm-1 and 588cm-1. These results show that the mode quality of these lasers is high and the single-mode tuning range is wide.

We have calculated the lasing process in a continuously pulsed CuCI laser with rate eqations and found that the calculation converges rapidly in the iterative procedure with a set of carefully chosen initial values. Therefore, solutions can be obtained on a microcomputer. The relation between the laser output and tube wall temperature has been studied. Eesults indicate that Cl~ anions are important for the laser output.

This article describes the design principle, design method and characteristics in structure of a fluorescence image multiplier used to examine early intramural carcinomas or neoplasms. Its clinical values are also evaluated.

The experimental multiphoton ionization(MPI)mass spectrum of CH3I at 308nm is reported. The dependence of the yields of I+ and CH3I+ ions on the sample pressure and laser pulse energy have been measured. The fragmentation mechanism of CH3I at 308nm is suggested, which involves competition between two MPI-fragmentation pathways.

Isothermal degorption kinetics of arachidic acid molecules in Langmuir-Blodgett multilayers is studied with attenuated total reflection method. A simple model has been proposed to analyse the thermal desorption process of the multilayer system. The calculated desorption energy between two neighboring molecular layers with hydrophobic ends against hydrophobic ends was found to be 19 kcal/mol; while with hydrophilic ends against hydrophilic ends, the energy was found to be 27 kcal/mol.

The reflection wave of a cone beam, which is formed by a linearly polarized plane wave through a convergence system and then incident upon a stratified medium, is analyzed. The reflection phase shift in the whole aperture and the dispersion are figured out by using the expression of the electric field strength which is derived in the paper. Furthermore, aberrations can be discussed while the multilayer thin film is regarded as an element of an imaging system. In addition, an expression of the intensity distribution of the interference field produced by two reflection waves with the initial waves of SM (the electric vector is perpendicular to the plane of main ray incidence) and PM (the electric vector is parallel to the plane of main ray incidence), is deduced. Specially applied to a multilayer composed of seventy-one layers, the numerical calculation conforms to experimental results quite well.

This paper describes the anodization of germanium in an oxygen-plasma excited by a high-frequency electromagnetic field. The refractive index of the plasma-anodized GeO2 film is about 1. 66. The transmittance of the oxide film on Ge was measured on an IR-450S type infrared spectrophotometer. The experiments show that infrared absorption bands of the GeO2 film are at 870cm-1 and 560 cm-1. The stretching constant of the Ge-O bond α (439N/m) and the Ge-O-Ge bond angle θ(129°) were calculated from the infrared were calculated from the infrared absorption data together with the edges of vibration bands predicted by the center-force-network model of Sen and Thorpe.