针对基于三个2×2单模光纤耦合器的全光纤级联Mach-Zehnder干涉仪型(CMZI)不等带宽光学梳状滤波器在实际制作过程中存在的问题，提出了由一个2×2和两个3×3单模光纤耦合器级联组成的全光纤不等带宽光学梳状滤波器，并进行了详细的分析。通过对光纤耦合器分光比、干涉仪臂长差等结构参量的选择，详细分析了其传输特性，并选取了理论优化计算的一组数据进行实验。 数值分析和实验结果表明：该器件将50 GHz的输入信号分离成信道间隔为100 GHz的奇偶两路输出信号，一路信道用于10 Gb/s传输，另外一路信道用于40 Gb/s传输。与全光纤CMZI型不等带宽光学梳状滤波器相比，其最大的优点是在实际制作时可以对每个光纤耦合器的分光比进行准确的监视和控制，降低了全光纤不等带宽光学梳状滤波器的制作难度。最后进行了实验研究，实验所得结果与理论结果相吻合。

An all-fiber asymmetric optical interleaver of cascaded Mach-Zehnder interferometer using a 2×2 and two 3×3 fiber couplers is developed. Influences on its transmission characteristics by such factors as splitting ratio of the directional fiber couplers and the physical length differences of the interferometer arms are numerically analyzed in detail. One set of optimized data is validated in the experimental result. The results of numerical simulation and experiments show that all-fiber optical interleaver with -3 dB passband in odd channels and even channels can be obtained for transmission speed of 40 Gb/s and 10 Gb/s, respectively. Compared with all-fiber asymmetric optical interleaver of cascaded Mach-Zehnder interferometer using three 2×2 fiber couplers, the most advantage of the present method is that the coupling ratio of couplers can be controlled in the fabricating process accurately. Finally, a novel structure of interleaver is fabricated using fused biconical taper technics in experiment. The experimental results agree with the analytical ones well.