Some phenomena were observed when the HgCdTe(PC,PV) detectors were irradiated by off2band CW CO2 laser which are much different from that when irradiated by in-band light. It is shown that the detectors' major response to the irradiation of in-band light is optical effect while that to the irradiation of off-band light is thermal effect.

To alleviate gain narrowing, the interference filter and the quartz birefringent filter were used to shape the spectrum of ultra-short pulse with the FWHM bandwidth of 13 nm at λ = 1053 nm. The parameters of quartz plate were decided by simulation with computer. The experimental result is coincident with the simulation of the spectrum shaping. The shape of the spectrum becomes flat at its top and the FWHM bandwidth broadens 2 nm.

A method is proposed for the optimization of the cavities of solid-state lasers with self-mode locking by the means of self-focusing. The feasibility of using cavities with two, three, and four mirrors for this purpose is discussed.

The changes of reflection spectrum and dispersion of fiber Bragg grating(FBG) apodized by moiréeffect are analyzed theoretically. It is pointed that the apodization of the fiber grating by using Moiréeffect is a pure apodization because the Moiré effect makes the index modulation amplitude in both positive and negative sides and keeps the average index unchanged. However, there exist some side lobes in short wavelength side of Bragg peak when the fiber Bragg grating was apodized by conventional raise cosine function because of the F-P effect. Experimentally apodized FBG by using Moiréeffect was obtained with a side mode suppression 6 dB better than conventional FBGwithout apodization.

This paper introduces algorithm of computing digital grating based on acousto-optic modulator for 3D holographic imaging. A new method of computing basis fringe by wavelet transform is proposed. Basis fringe function is computed and basis fringe model in physics is realized. Experimental results show that arithmetic is obvious advantage and robustness.

Austenite type surface coating was produced using pure Cr and Ni powders and slagging elements B and Si on 45# steel with light beam alloying. The effect of alloying process on appearance, microstructure and phase of alloying coating was investigated by SEM, EDS, X-ray diffraction, etc. The results show that appearance and microstructure of alloying coating are not only determined by heat input, but also relevant to dosage of slagging elements B and Si when dosage of alloying elements is invariable. Dosage of slagging elements B and Si has to be increased for good appearance of alloying coating while heat input is increased. Microstructure of alloying coating produced by low heat input is composed of the great mass ofγ(Fe,Ni) and a small quantity ofα(Fe2Cr) at γ(Fe,Ni) boundary while there isγ(Fe,Ni) + Cr2B eutectic at γ(Fe,Ni) boundary of alloying coating produced by high heat input.

Fundamental experimental study on nano-Al2O3 bulk materials produced by selective laser sintering technology was achieved. At the same time, SEM and X-ray analysis were used to analyse the microstructure of the sample of bulk materials. The result shows that the nano-Al2O3 powder materials can be sintered to bulk materials with the proper process parameters. The bulk material is compact and behaves the sub-structure, and the grain dimension of it is close to the original dimension of powder materials.

An experimental study of Yb-doped double-clad fiber laser in various optical configurations operating in self-Q-switched, AOM Q-switched and hybrid Q-switched conditions is presented. The fiber with a D-shaped inner cladding is pumped by a multi-mode laser diode with high power at 976 nm. Three thresholds of the Q-switched fiber laser are observed and analyzed. And the characteristics of the output pulses are studied experimentally in detail. Pulses with duration of ns, peak power of about 200 kW and the repetition rate of kHz are obtained. The results of the experiment are explained qualitatively.

A section of G. 652 fiber was spliced into the Yb-doped ring fiber laser as multimode fiber for lasing light. This combination of fiber types acts as a wavelength-dependent dynamical comb-like filter in the laser through spatial mode beating. Up to six stable laser wavelengths can be obtained in the region of 1030 nm with spectrum linewidth of 0. 15 nm and SMSR of 40 dB. By adjusting the polarization state of the light, the number of lasing wavelength and its space can be controlled.

The cesium atomic fountain used laser cooling and trapping is a new generation primary frequency standard. In this paper, it has been reported a series of measurements on the toss signal; published the fundamental estimated formulae for TOF signal and discussed the comparison between the experimental and calculated results.

A new BiB3O6(BIBO) crystal and its optical properties were reported. This article presents the phase-matching-angles of third-harmonic-generation(THG) of Nd:YAGlaser(1064 nm) and second-harmonic-generation(SHG) of 946 nm. The THG experiments of BIBO crystal with length of 6 mm were performed using Q-switched Nd:YAGlaser and the conversion efficiency of this crystal from 1064 nm to 355 nm was 19.2%.

In this paper, the noise theory of monolithic multi-quantum-well passively mode-locked laser diodes (MLLDs) is discussed, and the phase variation curve with carrier population of MLLDs is found. Therefore, it is important to understand the dynamic theory of mode-locked laser diodes in order to reduce its noise for fibre-optic communication system.

This paper presents a new method of preparation of VO2 thin film with a good performance and studies its microstructure, optical and electrical properties. The test results show that comparing before and after phase transition, the resistivity changes about 103 orders, and the IR transmittance changes up to 60%.

Optical properties of oxygen-doped Ge-Sb-Te thin films prepared by RF-sputtering method in the region of 400～800 nm were studied, including refractive index, extinction coefficient. The results show that optical constants of the Ge-Sb-Te-O films change with oxygen content and heat-treatment. XRD spectra of the films with different oxygen content in the as-deposited and heat-treated states show that the films changed from amorphous to crystalline states due to heat-treatment. The effect of the strain field induced by oxygen-doping on optical properties is discussed.

In this paper, a novel long-period fiber grating(LPFG) sensor written by high-frequency CO2 laser pulses is demonstrated for simultaneous measurement of transverse load and temperature. Such a sensor could solve the cross-sensitivity problem between transverse load and temperature due to the unique features of the LPFG, i. e. the load-sensitivity of the LPFG against the resonant wavelength shift strongly depends on loaded orientation. Within the circular position 0°～180°, there are one orientation which is the most load-sensitive, corresponding to the resonant wavelength“red”shift and another orientation which is the most load-sensitive, corresponding to the resonant wavelength“blue”shift, in particular, there are two special orientations, which are the most load-insensitive.

This paper brings forward a new method which can measure the phase delay and mark the placement of the fast and slow axis of wave plate at the same time. The measured wave plate is placed between polarizer and analyzer, and uniformly revolves under the control of stepping motor drived by computer. The curve of emergent light intensity vs time is obtained through continuous measuring the emergent light intensity. The phase delay can be calculated and the placement of the fast and slow axis of the wave plate can be marked after analyzing the curve. The process of experiment is controlled by computer, so the manipulation is sample, further more, it can avoid error originated from the limit of eyes′distinguishability and the inaccuracy of manual regulation, as a result, it has high degree of accuracy.

A novel method is proposed to improve the sensitivity of DOP(degree of polarization) ellipsoid on the polarization mode dispersion(PMD) in 40 Gb/ s non-return-to-zero(NRZ) systems by using optical bandstop filters. The effects of filter′s bandwidth on the three axes of DOP ellipsoid are investigated numerically. The results show that the sensitivity of DOP ellipsoid on differential group delay(DGD) and principal state of polarization(PSP) rotation rate is greatly improved by using a filter. Considering the loss induced by the filter, the bandwidth of the filter should be limited under 10 GHz when the maximum DGD is equal to 20 ps. Additionally, the results also show that the polarization dependent chromatic dispersion(PCD) which is smaller than 40 ps2 has less effects on the three axes of DOP ellipsoid when the bandwidth of a filter is equal to 10 GHz.

The system difference between the link of cascaded line-amplifiers and the link of cascaded optical add-drop-module(OADM) / optical cross-connection(OXC) nodes is pointed out. A new formula to estimate the optical signal-to-noise ratio(OSNR) for the link with cascaded OADM/ OXC nodes in all-optical network(AON) is presented. Based on the formula, a set of OSNR results is given. The analysis and numerical result show that the OSNRformula for link with cascaded line-amplifiers, which is widely used in engineering designing, could not be applied directly in AON design without correction.