基于琼斯矩阵的FIR晶体光滤波器设计方法

Jones Matrix Based Synthesis for FIR Optical Filter Uusing Birefringent Crystals

FIR晶体光滤波器由夹在两个偏振片之间的N个厚度相同的晶片构成,设计过程中需要根据要求的频率响应求出各个晶体波片的光轴方向和输出端偏振片的通光方向.提出了一种基于琼斯矩阵的反向递推设计方法.FIR晶体光滤波器的琼斯矩阵是各个晶片以及偏振片琼斯矩阵的乘积,利用这一关系可以建立简单的反向递推关系,并计算出与输出偏振分量对应的正交偏振分量,通过迭代运算确定所有元件的角度参数.实例设计的结果与使用其它方法得到的结果一致,设计过程简单.

FIR optical filter using birefringent crystals consists of N cascaded crystal waveplates with the same thickness between an input and an output polarizer. The variables determined by synthesis procedure are the angles of the optic axes of the crystal waveplates and the angle of the output polarizer. A Jones matrix based step-down iteration synthesis procedure for filter of this kind is proposed. Jones matrix describing such filters is the product of Jones matrixs of waveplates and polarizers used in filter. A simple step-down iteration relation and the orthogonal frequency response correspond to frequency response of filter is determined by this condition. The experimental result agrees with that provided by the reference and shows that the synthesis procedure is simple.