微环谐振器辅助马赫-曾德尔干涉仪滤波性能分析

Characteristic Analysis for Micro-ring Resonator Assisted Mach-Zehnder Interferometer Filter

为改善普通马赫-曾德尔干涉仪(MZI)滤波器的滤波性能,本文将微环谐振器与MZI相结合,设计出一种新型的微环辅助MZI型滤波器。文章采用信号流程图法推导出该结构的传递函数,并对模型输出特性进行仿真分析。结果表明:当滤波器结构采用非平衡型MZI时,通过引入微环的反馈调节机制,优化耦合系数,发现滤波器输出谱具有窄带高消光比特性;当采用平衡型MZI时,通过对滤波器参数的优化,实现滤波器输出端最大平坦滤波响应,阻带抑制(>40 d B),具有良好的滚降特性。与普通MZI滤波器相比,本文提出的微环辅助MZI型滤波器滤波性能有了明显改善。

To improve the filtering performance of conventional Mach-Zehnder interferometer(MZI)filter,a novel structure which combining ring resonator with MZI is proposed in this paper.Transfer function of the improvement filter was established by using the Signal Flow Graph and the characteristic of the output spectrum was simulated as well.The results of numerical simulation indicate that when MZI with the length difference of interference arms is chosen,through the phase modification provided by the ring resonator and the optimization of the coupling coefficient,the spectrum of output port has the properties of narrow band with high extinction ratio.When the MZI with the length identical of interference arms is adopted,by optimizing the parameters of the structure,a maximum flatness filtering response is obtained,the isolation in stopband(>40dB)and the rolloff in transition band are strengthened.Compared with the filtering performance of conventional MZI filter,the novel optical filter proposed in this paper improved the performance obviously.