提出了一种由嵌入式环谐振腔和Mach-Zehnder(M-Z)干涉仪组成的新颖带通滤波器, 嵌套环是在环谐振腔的基础上, 引入一个类似双线耦合环谐振器的外谐振环。依据耦合模理论推导出滤波器传递函数, 并分析了环的光学长度、耦合系数和内外环长度比对其影响。模拟结果证明, 通过改变结构参数, 滤波器的中心波长和带宽可调, 中心波长在1520nm~1600nm波段任意可调, 带宽调整范围可达0.2nm~102nm。且保持输出波形有较高的平坦度和较低的旁瓣, 可满足通信系统宽带及超窄带带通滤波器的设计要求。

A new bandpass filter that consists of an embedded ring resonator and the Mach-Zehnder interferometer is proposed. On the basis of the ring resonator, an out-ring resonator which consists of an embedded ring resonator is introduced. Based on the coupled-mode theory, formulas of parameters and the influence of the output waveform are derived and analyzed. Simulation results show that the designed filter’s center wavelength and bandwidth is tunable by changing parameters of the structural, the central wavelength is tunable ranging from 1520 nm to 1600 nm, and the bandwidth varies from 0.2 nm to 102 nm. The output waveform also has high flatness and low side-lobe output during the whole tuning range. The method can be used in the broad and narrow bandpass filter in the communication system.