提出了一种具有方波形输出谱的级联马赫-曾德尔光纤干涉仪型梳状滤波器的优化计算方法。利用传输矩阵法将级联马赫-曾德尔光纤干涉仪的输出光谱表示为显式函数，采用独特的递推方法将理想的梳状滤波器的方波型输出函数展开，当这2个函数的系数对比时，有时候没有精确解，此时利用Matlab，通过特别的优化计算，可以得到级联马赫-曾德尔光纤干涉仪的近似结构参数，使其输出谱近似为方波。设计实例表明：此种优化计算方法非常方便、灵活和有效。

An optimization calculation of interleaver made of cascade Mach-Zehnder fiber interferometer with square wave is put forward. Based on transmit-matrix, the output spectrum from the cascade M-Z interferometer can be expressed as explicit function, the square wave output function of perfect interleaver can be expanded in a unique recursion way. Sometimes there is no accurate outcome when the terms of the two functions are compared, but approximate structureparameter of cascade Mach-Zehnder fiber interferometer can be obtained by optimizing calculation method with Matlab, which can make the output-spectrum an approximate square wave. The design example indicates that this method is convenient, flexible and effective.