提出了一种金属修饰的微结构光纤偏振分束器,并且利用全矢量有限元法仿真分析了该偏振分束器的长度与其结构参数的关系, 进而得出了该偏振分束器长度随孔间距、占空比变化的一般规律。研究结果表明: 当其他结构参数一定时, 该偏振分束器长度会随着孔间距的减小而减短; 占空比减小, 偏振分束器长度也会随之减短。最终综合考虑其性能与金属材料带来的损耗的影响, 设计出一种结构简单的微结构光纤偏振分束器。该偏振分束器长度为3.523 mm, 在其工作波长1.55 μm处消光比高达74.9 dB, 消光比高于20 dB的波长范围为1.53~1.57 μm之间的40 nm范围, 覆盖了整个光通信的C波段范围。并且该偏振分束器有着较好的冗余特性, 在偏振分束器长度存在±5%的误差时, 仍能保持较好的性能。

A polarization splitter based on metal-decorated microstructure fiber was proposed. The relationship between splitter length and structure parameters was analyzed by using full vectorial finite element method. The variation rules of splitter length with hole pitch and duty ratio for the polarization splitter were obtained. Numerical results shows that the length of the polarization splitter decreases with the decrease of hole pitch and the ratio of hole diameter to hole pitch. Considering both the properties and the transmission loss caused by metal, a simple-structure polarization splitter based on metal-decorated microstructure fiber was optimized. The length of the polarization splitter is as short as 3.523 mm and the extinction ratio reaches up to 74.9 dB at the wavelength of 1.55 μm. The bandwidth is 40 nm from 1.53 μm to 1.57 μm where the extinction ratios are more than 20 dB covering the C band of optical communication. At the same time, when the length of polarization splitter exists ±5% error, it can also keep good performance.