环形谐振器辅助马赫-曾德尔干涉仪型波长交错滤波器的研究

Study of Interleaver Based on Ring Resonator Assisted Mach-Zehnder Interferometer

将环形谐振器与马赫-曾德尔干涉仪相结合,利用谐振器反馈回路引入的相位调节效应,选择合适的谐振器耦合角,设计出一种具有最大平坦滤波响应的环形谐振器辅助马赫-曾德尔干涉型波长交错滤波器。与普通马赫-曾德尔干涉型波长交错滤波器相比,不仅阻带抑制(>38dB)和过渡带滚降特性明显加强,而且在通带中心15GHz范围,将色散降低到±10ps/nm以内,从而可以有效避免对传输信号造成失真。在此基础上,进一步研究环周长(Lr)与马赫-曾德尔干涉臂长差(ΔL)之间的关系,指出波长交错滤波器奇偶输出端口的带宽分配比直接决定于Lr/ΔL,当调整Lr/ΔL=1/2,可以实现具有1∶2非对称带宽分配特性的新型波长交错滤波器,为10Gb/s向10Gb/s+40Gb/s系统升级提供一种简单、灵活的方式。

An interleaver combining ring resonator with Mach-Zehnder interferometer （MZI） is proposed. Based on the phase modification provided by the ring resonator, a maximum flatness filtering response is obtained by optimizing the coupling angle of resonator. Compared with the traditional MZI, the isolation in stopband （〉38 dB） and the rolloff in transition band are strengthened, but also the dispersion in passband is reduced to ± 10 ps/nm in the center frequency range of 15 GHz which eliminate the distortion of transmission signals. Furthermore, the influences of ring circumference （Lr） on length difference （△L） of MZI arms are investigated, and the bandwidth allocation of oddeven ports is directly determined by Lr/△L. The result demonstrates that a novel interleaver with 1：2 asymmetric bandwidth allocation can be achieved by adjusting Lr/△L = 1/2. This kind of interleaver will make system upgrade from 10 Gb/s to 10 Gb/s＋40 Gb/s in a more simple and flexible way.