非互易波导光栅的滤波特性与应用

根据磁光材料的非互易特性和波导光栅的滤波特性,介绍了一种磁光波导光栅的非互易滤波特性及其应用.该磁光波导光栅采用法拉第旋转系数为4800°/cm的掺铈钇铁石榴石(Ce:YIG)材料、单模的脊型补偿墙截面结构和cosine型变迹光栅结构的设计.利用有限差分法和等效折射率法模拟该磁光波导光栅非互易效应的大小,同时结合耦合模理论和转移矩阵法对该磁光波导光栅的非互易滤波特性进行分析.结果表明,对于TE模和1550 nm波段,该磁光波导光栅正反向传输的中心波长偏移0.8 nm,带宽0.4 nm(-20 dB).这种非互易滤波特性可以用来实现波长选择光隔离器和光分插复用器(OADM)等集成光学器件.

Filtering Characteristic and Application of the Nonreciprocal Waveguide Grating

According to the nonreciprocal characteristic of magnetooptic material and the filtering characteristic of waveguide grating, the nonreciprocal filtering characteristic and the application of magnetooptic waveguide grating are presented. YIG crystal doped by Ce (Ce:YIG) with Faraday rotation angle (ΘF) of 4800 °/cm, rib section of compensation wall of single mode and apodizer grating of cosine type are chosen to design the magnetooptic waveguide grating. The method of finite-difference and equivalent effective index are used to simulate the intensity of the nonreciprocal effect of the magnetooptic waveguide grating. Besides, coupled-mode theory and transfer matrix method are also used to analyze the nonreciprocal filtering characteristics of the magnetooptic waveguide grating. The result indicates that for transverse electric (TE) mode and the wave band of 1550 nm, the forward center-wavelength of the magnetooptic grating is shifted by 0.8 nm relative to the backward center-wavelength and the bandwidth is 0.4 nm (-20 dB). This kind of nonreciprocal filtering characteristic can be applied to integrated optical devices such as nonreciprocal isolator and optical add-drop multiplexer (OADM).