一种级联两个IIR滤波器的微波光子滤波器的特性分析

The Characteristic of Microwave Photonic Filters Using Cascaded Two IIR Filters

摘要: 本文给出了一种可调的高Q值的带通微波光子滤波器(Microwave Photonic Filters, MPFs)，它由两个级联的无限脉冲响应(Infinite Impulse Response, IIR)滤波器组成。对其进行了详细的理论分析，讨论了两个IIR滤波器的耦合系数k₁，k₂，k₃、掺饵光纤环的增益g和光纤环的长度L₁和L₂对微波光子滤波器滤波性能的影响。通过理论计算和仿真分析可知，在IIR1滤波器的耦合系数为k₁ = 0.5、掺饵光纤环增益为2、IIR2滤波器的耦合系数k₂ = 0.5，k₃ = 0.9、两个光纤环长度相等时，得到的微波光子滤波器的滤波效果最佳。

Abstract: A kind of adjustable bandpass microwave photonic filters (MPFs) that can realize a high Q value is presented in the paper. It consists of two cascaded infinite impulse response filters. The theory of it was detailed analyzed, and the paper discussed the influences on the filtering performance of microwave photonic filters the coupling coefficient k₁, k₂, k₃ of the two IIR filters, the gain of Er-doped fiber ring g, the fiber ring length L₁, L₂of the two IIR filters. Theoretical calculation and simulation analysis indicate that the best filtering effect of the microwave photonic filters can be obtained when the coupling coefficient of the IIR1 filter is 0.5, the gain of Er-doped fiber ring is 2, the coupling coefficient of the IIR2 filter is k₂ = 0.5 and k₃ = 0.9, and the fiber ring length of the two IIR filters is equal.