为提高MZI(马赫-曾徳干涉仪)型交错滤波器的输出光平坦度, 扩大信道带宽, 提出了由1个3×3和两个2×2单模光纤耦合器组成的全光纤级联MZI型交错滤波器, 用传输矩阵法推导出了模型的输出谱和相关参数之间的表达式并进行了特性分析。结果表明: 当耦合器的分光比和光纤干涉臂之差为定值时, 可以产生理想的交错谱图。这种滤波器信道间隔为2 nm。此外应用双环光纤辅助的方法可使得输出波形的顶端更加平坦, 边模抑制比贴近理论值。

In order to improve the output of the optical flat-top extent and expand the channel bandwidth of interleaver filters, an all-fiber cascaded Mach-Zehnder Interferometer (MZI)-typed interleaver filter consisting of one 3×3 and two 2×2 single-mode fiber couplers is developed. The expression between the output spectrum of the model and its relevant parameters is deduced using the transfer matrix method and its characteristics are analyzed. The result shows that an ideal interleaving spectrum can be produced when the difference between the coupler splitting ratio and the fiber interference arms are constant. This filter has a channel interval of 2 nm and, when assisted by double-ring fibers, its output waveform is still more flat-topped and the side-mode suppression ratio is close to the theoretical value.