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.

M-Z光波导是有机聚合物电光调制器的重要结构单元。将有效折射率法与二维差分束传播法相结合,利用有效折射率法计算了聚合物脊形波导的横向折射率分布及有效折射率。由Maxwell方程出发,结合辐射透明边界条件,采用Crank-Nicholson差分格式,得出有限差分束传播法的计算格式。通过对M-Z型波导结构中TM模的传播及损耗特性进行理论分析,研究了以IPC-E(20wt%)/PSU作为芯层材料的脊形M-Z波导,并对其结构进行了优化设计,得到了较为满意的结构参数。

分束器是光纤通信系统中光无源网络和光子集成回路的重要器件。1×2 MMI(multimode interferences)电光有机聚合物分束器是利用自成像效应设计的。分析了1×2 MMI的工作原理。利用有效折射率方法(effective index method, EIM) 计算出1×2 MMI三维多模脊形波导的有效折射率分布。利用自成像效应的成像规律计算出成像位置并用导模传输分析法(guided-mode propagation analysis, MPA)对输出波导的光强进行模拟。分析表明: 在波长为1.55μm的情况下，1×2 MMI的输出波导的光强在未加电极时可以实现预定分束比输出; 加上电极之后，由于电光效应可调控有机聚合物波导折射率的改变，利用有限差分光束传播法模拟输出波导的分束比可在7.6dB范围内可调。