基于光纤干涉器的带通巴特沃斯光学滤波器的设计

The Design of Bandpass Butterworth Optical Filter Based on Optical Fiber Interferometer

光学滤波器在光信号处理和通信系统中有着重要的作用。研究带通巴特沃斯光学滤波器的设计过程,这种滤波器的实现以级联结构形式给出,利用一臂上附有光纤环的Mach-Zehnde(rM-Z)光纤干涉器来实现传输函数的零点和极点,光纤环上加有掺铒光纤放大器(EDFA)来放大光信号。通过级联一臂上附有光纤环的M-Z光纤干涉器来实现滤波器的传输函数。根据传输函数的零极点计算出了M-Z光纤干涉器的各个耦合器的耦合系数、臂长差和环长,并对其进行了计算机仿真,验证了光学滤波器的频谱特性。

Optical filters play a significant part in optical signal processing and communications systems.A systematic procedure for designing bandpass optical filters of Butterworth types is researched in this paper.The implementation of these filters in cascade forms are given using Mach-Zehnder（M-Z） optical fiber interferometers with a optical fiber ring in one arm exihibiting zeros and poles of the transfer function and the optical signal ampli ed by an erbium-doped ber ampli er（EDFA） and canscading M-Z optical fiber interferometer with a optical fiber ring in one arm for implementation of the designed filter function.the coupler＇s coefficients,the optical path differences of M-Z optical fiber interferometers and the length of the optical fiber rings are determined by the zeros and poles of the transfer function.furthermore,the frequency spectrum characteristics of the optical filters were verified through computer simulation.