Simultaneous Measurement of Particle Size and Particle Velocity by the Spatial Filtering Technique

The objective of this study was to compare the measuring results of a fiber‐optical probe based on a modified spatial filtering technique with given size distributions of different test powders and also with particle velocity values of laser Doppler measurements. Fiber‐optical spatial filtering velocimetry was modified by fiber‐optical spot scanning in order to determine simultaneously the size and the velocity of particles. The fiber‐optical probe system can be used as an in‐line measuring device for sizing of particles in different technical applications. Spherical test particles were narrow‐sized glass beads in the range 30–100 μm and irregularly shaped test particles were limestone particles in the range 10–600 μm. Particles were dispersed by a brush disperser and the measurements were carried out at a fixed position in a free particle‐laden air stream. Owing to the measurement of chord lengths and to the influence of diffraction and divergent angle, the probe results show differences from the given test particle sizes. Owing to the particle‐probe collisions, the mean velocity determined by the probe is smaller than the laser Doppler mean velocity.     

高效率窄线宽光纤激光器

本文报道了一种环形腔掺饵光纤激光器，得到了泵浦效率高达22.6%，输出线宽小于0.1nm的激光输出。     

Theoretical Discussion of Couple-Mode Using Chirped Fiber Grating for Dispersion Compensation

１ＩｎｔｒｏｄｕｃｔｉｏｎＡｔｐｒｅｓｅｎｔ，ａｓｔｈｅｅｒｂｉｕｍｄｏｐｅｄａｍｐｌｉｆｉｅｒｓｈａｖｅｓｕｃｅｓｆｕｌｙｂｅｅｎａｐｐｌｉｅｄｔｏｏｐｔｉｃａｌｆｉｂｅｒｌｉｎｋｓ，ｔｈｅｌｏｎｇｈａｕｌｈｉｇｈｂｉｔｒａｔｅｏｆｏｐｔｉｃ...     

YAG激光熔覆的研究现状与发展趋势

本文介绍了YAG激光熔覆的特点，并与CO2激光进行了比较，显示了YAG激光熔覆的优势和潜力。叙述了YAG激光熔覆的研究进展及其应用前景。     

论网络升级方式与光纤选择的关系

在重点说明影响传输光纤设计的主要问题的同时，简要介绍了各种升级方式所面临的主要技术挑战，并详细说明这些挑战对传输光纤提出的技术要求。     

应用LiNbO_3声表面波驱动的全光纤声光频移器

介绍一种工作在10.7MHz的全光纤声光频移器.它由在LiNbO_3基片上制作的叉指电极换能器产生的声表面波驱动.当驱动电功率1.5W时,频移光转换效率达35％.     

Acousto-optic mode coupling of partially coherent light in two-mode optical fibers

An acoustic pulse propagating on a two-mode fiber can act as a beam splitter in a scanning interferometer. When this device is employed in white-light interferometry, the effects of distributed coupling and dispersive interferometer arms need to be considered. A theory suitable for treating acousto-optic interaction of partially coherent light in a moving interaction region was developed. It was found that differential optical dispersion should be negligible and the acoustic pulse length short. Also the coherence time should be short but long compared to the intermodal group delay difference over a pulse length. Experiments with long acoustic pulses were performed, and fairly good agreement with theory was obtained.     

时分复用倍乘光脉冲重复率的新型光纤耦合器环状连接法分析

提出并详细分析了一种基于时分复用技术倍乘光脉冲重复率的方法：在２×２光纤耦合器的一个输入口与一个输出口间，接入时延为脉冲列半周期奇数倍的一段光纤使之形成环状连接循环耦合，而在另一输出口获得光脉冲。详细分析了该系统中光纤耦合器耦合比、插入损耗、时延光纤长度的要求，偏差的影响及其调节法，给出了理论公式、结果的计算机模拟与实验介绍；与经典的马赫陈德尔干涉仪接法及近年提出的Ｓａｇｎａｃ环接法进行了比较。该方法特别适用于对窄脉冲列进行串接复用实现重复率的多次倍乘，从而得到数千兆赫至上百千兆赫的高重复率光脉冲     

光激励和光检测微型硅谐振器研究

分析了光激励谐振器振动的检测问题，用调制激光束激励谐振器使其发生振动，并采用光学干涉的方法测量了这种微振动。     

Optical current transducers using flint glass fiber as the faraday sensor element

This paper describes development of the optical current transducers using flint glass fiber as the Faraday effect sensing element. Excellent polarization properties of the fiber with low birefringence are described, and the design and test data of a current transducer using the fiber manufactured for use in electric power facilities are reviewed. Experimental results on flexible characteristics of a scheme with round trip light transmission in the fiber is also reported.