设计了一种基于二维光子晶体的偏振滤波分束器.利用平面波展开法计算光子晶体带隙, 确定入射光波1 550 nm下获得单偏振光的微结构参数, 利用时域有限差分法对90°弯折缓冲层和分支冲击壁进行优化.分束器实质为在二维光子晶体阵列中引入缺陷而构成的波导, 利用光子带隙效应和线缺陷90°偏转将入射光中的TM偏振分量(或TE偏振)完全过滤, 得到单偏振光, 最后通过Y型分支实现1∶1的单偏振光分光输出.仿真结果表明总输出/输入功率比达到68%.

A kind of beam-splitting polarizing filter based on two-dimensional photonics crystal was proposed.The photonic bandgap was calculated by plane wave expansion method to confirm the micro-structure parameters,with which single polarized beam in 1550nm can be obtained;Finite-different time-domain method was used to optimize the 90° bending buffer layer and impacting wall of beam-splitter.This device indeed is a waveguide fabricated by introducing defect in two-dimensional photonics crystal array,a single polarization source can be obtained by using photonics band gap and 90° linear defect to filter a certain polarization completely off.By the construction of Y-shaped defect,an approximate splitting ration of 1: 1 is achieved.Through the optimization of the 90° linear defect and buffer layer,a ratio of 68% between the output power and input power is finally gained.