Polarization analysis and experimental implementation of PLZT electro-optical switch using fiber Sagnac interferometers

The polarization characteristics of electro-optical (EO) switches using fiber Sagnac interferometer (FSI) structures are theoretically investigated. Analytical solutions of output fields are presented when the twists and birefringence in a Sagnac loop are considered. Numerical calculations show that the twists of fiber, the orientation of the inserted phase retarder, and the splitting ratio of the coupler will influence both the output intensity and the output polarization properties of the proposed switch. A polarization-independent EO switch based on a Sagnac interferometer and a PUT bar was experimentally implemented, which showed good coincidence with the analytical results. The experiment showed a switch with 22 dB extinction ratio and less than 31.1 ns switching time. (c) 2006 Optical Society of America.

基于PLZT的电光偏转器的特性研究

采用具有高二次电光效应的掺镧锆钛酸铅陶瓷材料（PLZT），设计和制备了一种基于折射率随外加电压发生变化的电光偏转器。构建了测试系统，测得PLZT的电光系数是R33=2.1

Experimental investigation of optical beam deflection based on PLZT electro-optic ceramic

Based on the optical characteristics of PLZT electro-optic ceramic, two kinds of electro-optic deflectors, triangular electrode structure and optical phased array technology, are studied in detail by using transverse electro-optic effect. Theoretically, the electro-optic deflection characteristics and mechanisms of the deflectors are analyzed. Experimentally, the optical characteristics of ceramic wafer, such as the phase modulation, the hysteresis and the electro-induced loss characteristics, are measured firstly, and then the beam deflection experiments are designed to verify the theoretical results. Moreover, the effect of temperature on the performance of triangular electrode deflector is investigated. The characteristics of both deflectors are also compared and illuminated. (c) 2007 Optical Society of America.

Energy principle of ferroelectric ceramics and single domain mechanical model

Many physical experiments have shown that the domain switching in a ferroelectric material is a complicated evolution process of the domain wall with the variation of stress and electric field. According to this mechanism, the volume fraction of the domain switching is introduced in the constitutive law of ferroelectric ceramic and used to study the nonlinear constitutive behavior of ferroelectric body in this paper. The principle of stationary total energy is put forward in which the basic unknown quantities are the displacement u (i) , electric displacement D (i) and volume fraction rho (I) of the domain switching for the variant I. Mechanical field equation and a new domain switching criterion are obtained from the principle of stationary total energy. The domain switching criterion proposed in this paper is an expansion and development of the energy criterion. On the basis of the domain switching criterion, a set of linear algebraic equations for the volume fraction rho (I) of domain switching is obtained, in which the coefficients of the linear algebraic equations only contain the unknown strain and electric fields. Then a single domain mechanical model is proposed in this paper. The poled ferroelectric specimen is considered as a transversely isotropic single domain. By using the partial experimental results, the hardening relation between the driving force of domain switching and the volume fraction of domain switching can be calibrated. Then the electromechanical response can be calculated on the basis of the calibrated hardening relation. The results involve the electric butterfly shaped curves of axial strain versus axial electric field, the hysteresis loops of electric displacement versus electric filed and the evolution process of the domain switching in the ferroelectric specimens under uniaxial coupled stress and electric field loading. The present theoretic prediction agrees reasonably with the experimental results given by Lynch.

基于光纤环形镜的偏振无关的掺镧锆钛酸铅电光开关

利用掺镧锆钛酸铅（PLZT）陶瓷二次电光效应结合光纤环形镜结构的优势构成偏振无关高速电光开关。采用琼斯矩阵方法分析了光纤环形镜的输出特性，给出了开关消光比同器件结构参量之间的关系。测量掺镧锆钛酸铅电光开关具有输入偏振无关特性，光开关消光比达到25dB，响应时间小于3μs。此外利用此开关装置测量获得了实验用掺镧锆钛酸铅陶瓷的克尔系数为k～1．1×10^-16m^2／V^2。理论分析和实验结果表明，利用环形镜结构稳定优势和掺镧锆钛酸铅优良的电光特性结合设计的高速光开关具有良好的应前景。本工作对掺镧锆钛酸铅电光

基于掺镧锆钛酸铅电光材料的光学相控阵光束扫描器

基于掺镧锆钛酸铅(PLZT)电光陶瓷材料的光学特性,提出了一种具有上下电极结构的光学相控阵高速光束扫描器。在理论上,分析了具有这种结构的光学相控阵的光束电光偏转特性和机制;在实验上,分析了掺镧锆钛酸铅材料的相位调制特性和损耗特性,制作了相关的光学相控阵器件,并构建了相应的测试系统,获得了光束在空间的角度偏转,与理论分析结果相符。

基于电光材料的光学相控阵技术研究进展

综述了基于电光材料的光学相控阵(OPA)的研究进展。介绍了光学相控阵技术的基本原理以及不同电光材料(铌酸锂电光晶体,AlGaAs光波导,液晶和掺镧锆钛酸铅(PLZT)电光陶瓷)光学相控阵技术的基本构想和涉及的关键技术;着重介绍近年来基于PLZT电光陶瓷材料光学相控阵技术的发展情况以及在这方面的最新研究成果,包括单级相控阵、级联相控阵、不同电极结构(表面电极和上下电极结构)相控阵技术等;最后简要介绍了光学相控阵技术在激光雷达等军事领域中的应用。