In order to improve the transmission performance of the conventional Mach-Zehnder interferometer (MZI), a novel interleaver combining an “8” form ring resonator with a planar 3×3 single fiber coupler is proposed. Based on the phase modulation provided by the ring resonator, a flat filtering response is obtained by optimizing the coupling angle of resonator. The output expression is derived and numerical simulation is performed. The simulation indicates that the 0.5 dB passband and 25 dB stopband of the proposed interleaver are simultaneously improved remarkably, which are much wider than those of the single-stage MZI and the two-stage MZI interleavers, and the filtering performance of the proposed interleaver, which achieves a nearly square spectrum response, is also much better. Compared with the interleaver based on an asymmetrical MZI with a resonator in one arm, there is no difference between the intensities of two coherent beams in the condition of considering the influence of the propagation loss. Theoretical analysis shows that the influence of the propagation loss on extinction ratio can be effectively reduced.

为改善全光纤三端口Interleaver的输出特性, 提出了一种基于双“8”字型光纤谐振环的对称结构三端口全光纤Interleaver。该谐振环由一个一字型3×3单模光纤耦合器和两个2×2单模光纤耦合器组成双“8”字型作为输入耦合器, 而一个品字型3×3单模光纤耦合器作为输出耦合器。理论和实验分析了该波长交错器的输出特性, 结果表明: 与两级级联马赫-曾德尔干涉仪型(TCMZI)全光纤三端口Interleaver相比, 其输出波形通带更加平坦, 通带和阻带加宽, 信道间功率旁瓣降低了约24 dB。通过实验用光纤熔融拉锥法制作了该器件, 结果显示实验结果与理论分析吻合得很好, 实验样品的信道间旁瓣值小于-30 dB, 信道隔离度大于30 dB。

为改善全光纤三信道波长交错器的输出特性，提出了一种不对称结构的三光纤臂Mach-Zehnder干涉仪(A-MZI)，这种光纤干涉仪由一个一字型3×3 单模光纤耦合器和一个品字型3×3 单模光纤耦合器以及三条光纤干涉臂组成，其中一字型3×3 单模光纤耦合器作为输入耦合器，品字型3×3 单模光纤耦合器作为输出耦合器。推导了该器件的输出表达式，并进行了数值模拟。模拟结果表明，与常规的全光纤MZI型三信道波长交错器(C-MZI)相比，本文提出的交错滤波器的信道间功率旁瓣降低了约13.6 dB，并且具有对器件参数偏差不敏感等优点。用光纤熔融拉锥法实验制作了该器件，实验结果与理论分析吻合得很好，实验样品的信道间功率旁瓣值<－34.6 dB, 插入损耗< 1.0 dB，信道隔离度>30 dB。