为改善普通马赫曾德尔干涉仪(MZI)滤波器的输出性能，采用将双微环谐振器与马赫曾德尔干涉仪相结合，设计出一种新的滤波器结构。采用信号流程图理论分析得出该结构的传递函数，并对输出端口的透射谱进行数值模拟分析。仿真结果表明，与普通马赫曾德尔干涉仪滤波器相比，当选择合适的耦合系数，双微环谐振器辅助马赫曾德尔干涉仪滤波器的透射谱顶部平坦，形状类似于方形，自由光谱范围达到了19nm，锐度因子为1.16，消光比为54dB，品质因子为94.5，滤波性能得到较大改善。详细研究了耦合系数和微环半径对滤波器输出性能的影响。

To improve the transmission performance of conventional MachZehnder interferometer(MZI) filter, a novel filter adopting two resonator rings combining with MZI was proposed. Based on this structure, the filter’s transfer function was established by using the signal flow graph method and the output spectra were simulated as well. The results show that, compared with conventional MZI filter, when choosing appropriate coupling coefficient, the improved filter can give rectangular waves approximating flat top. The free spectral range up to 19nm, the sharpness factor of 1.16, the extinction ratio of 54dB and the quality factor of 94.5 were obtained, thus the transmission performance of this novel filter is improved obviously.The impact of the coupling coefficient and the radius of ring resonator on the output performance of this filter is discussed in detail.