一种测量光束横向尺寸的新方法

将吸收滤光片加工成柱面透置于光束束腰附近，可通过测量入射光功率和透射光功率得到以方差定义的光束横向尺寸，借助参数已知的附加透镜也能得到光束的Ｍ＾２和任意轴向位置的光束横向尺寸。文中给出了测量装置参数的造反依据和误差分析。     

Design Considerations of a Television Camera Detecting Oil Slicks on the Sea

This paper describes a television camera system that automatically captures exclusive images of an oil slick on the sea. The system includes two optical wavelength filters (WFs), two charge coupled devices (CCDs), and a differential image circuit that produces an absolute value of a difference signal between two output images from CCDs. The operating principle is based on the fact that, due to the multiple-beam interference in the oil slick, there is a marked difference of intensity between light reflected from the surface of the sea and that from the slick. The probabilities to sense slicks under various conditions were calculated using two types of WF, i.e., a space-invariant WF and a space-variant WF, and it was found that the latter was far superior to the former.     

A phase-shifted linearly chirped fiber Bragg grating with tunable bandwidth

We demonstrate a new method to broaden and adjust the transmission bandwidth of a phase-shifted linearly chirped fiber Bragg grating (PS-LCFBG) after its fabrication. A movable thermal head is used to heat the PS-LCFBG at a small contact point. The original ultra-narrow transmission bandwidth of the PS-LCFBG can be broadened due to both the presence of the passband peak caused by the thermally-induced temporary phase shift and the passband caused by the thermally-induced local Bragg wavelength shift. The transmission bandwidth of the new passband peak can be adjusted by changing the position of the thermal head. The transmission bandwidth of the PS-LCFBG can be broadened from <10 pm to 0.16 nm, and can be tuned from 0.16 to 1.05 nm.     

Fuzzy Ordered Filters in Implicative Semigroups

Animplicativesemilatticeisanalgebraicsystemhavingasmodelslogicalsystemsequippedwithimplicationandconjunction,butnotpossessingadisjunction.ImplicativesemilatticeswerestudiedbyW.C.Nemitz[5].In[2],T.S.BlythgeneralizedsomeresultsofW.C.Nemitz[5]byintroducingthenotionofaBrouweriansemigroup.FollowingtheideasofNemitzandBlyth,M.W.ChanandK.P.Shum[3]introducedthenotionofnegativelypartiallyorderedimplicativesemigroupsandgeneralizedsomeresultofNemitzonimplicativesemilatticestoim-plicativesemigroups…     

非线性干涉滤光片N形反射光双稳器件的研究

对Ｎ形反射光双稳器件的结构进行了理论设计和实验研究，对光双稳的重要参数δＩ０、δＩｒ与初始失调量δ之间的关系进行了描绘，并通过引入ＺｎＳｅ薄膜的色散关系，使这一理论方法具有自洽性。最后，文章给出了通过这一方法设计的非线性干涉滤光片Ｎ形反射光双稳器件的实验结果。     

镜面起伏对1.55μm Si基MEMS光滤波器的影响

用传输矩阵方法,在简化的光学模型基础上,分别讨论了分布式Bragg反射镜DBR(Distributed Bragg Reflector)的生长精度及镜面起伏对1.55 μm Si基MEMS(Micro-Electro-Mechanical-System)可调谐光滤波器透射谱的影响.计算表明:DBR生长误差仅使主透射峰位置发生变化,而镜面起伏是导致主透射峰性能劣化的主要原因,它使得FWHM增大,透射峰强度下降.理论计算结果能较好地解释实验现像.在此基础上,进一步讨论了引起镜面起伏的多种原因,并提出了可能的解决方法.     

采用电光效应实现双折射切趾的集成光学声光可调谐滤波器

声光可调谐滤波器（AOTF）是密集波分复用系统（DWDM）中的关键器件之一。影响该器件性能的一个主要因素是透过率曲线中旁瓣的存在。基于双折射切趾的原理，提出了利用LiNbO3 电光效应来实现切趾的新方案。对该方法进行了理论和实验两方面的研究，实验结果与理论基本相符。     

Digital holography particle image velocimetry for the measurement of 3Dt-3c flows

In this paper a digital in-line holographic recording and reconstruction system was set up and used in the particle image velocimetry for the 3Dt-3c (the three-component (3c), velocity vector field measurements in a three-dimensional (3D), space field with time history (t)) flow measurements that made up of the new full-flow field experimental technique—digital holographic particle image velocimetry (DHPIV). The traditional holographic film was replaced by a CCD chip that records instantaneously the interference fringes directly without the darkroom processing, and the virtual image slices in different positions were reconstructed by computation using Fresnel–Kirchhoff integral method from the digital holographic image. Also a complex field signal filter (analyzing image calculated by its intensity and phase from real and image parts in fast fourier transform (FFT)) was applied in image reconstruction to achieve the thin focus depth of image field that has a strong effect with the vertical velocity component resolution. Using the frame-straddle CCD device techniques, the 3c velocity vector was computed by 3D cross-correlation through space interrogation block matching through the reconstructed image slices with the digital complex field signal filter. Then the 3D-3c-velocity field (about 20 000 vectors), 3D-streamline and 3D-vorticiry fields, and the time evolution movies (30 field/s) for the 3Dt-3c flows were displayed by the experimental measurement using this DHPIV method and techniques.     

A Miniaturized Tunable Filter Based on a Fiber Bragg Grating Loaded by a Ceramic-Tube Microheater

A miniaturized 1.55 μm tunable fiber Bragg grating (FGB) filter is proposed and successfully demonstrated using an aluminum ceramic-tube with a tungsten thick film sleeve microheater. Fine tuning of the Bragg reflective wavelength with 0.0135 nm/^oC is achieved by adding the constant thermal distribution along the uniform FBG with a 0.3 nm bandwidth. Furthermore, a 1.5 nm linearly chirped reflection bandwidth is obtained by thermal gradient loading.