微纳光纤偏振分束器特性研究

The characteristics of the polarization beam splitters based on micro/nano optical fiber

采用3维全矢量光束传输法研究两相邻微纳光纤的偏振耦合特性,证实利用微纳光纤偏振耦合特性能很好地实现偏振分束,构成光纤偏振分束器.在保证偏振分束性能的条件下,通过研究微纳光纤偏振分束器的几何特性对偏振分束性能的影响,优化设计了微纳光纤耦合型偏振分束器,得到耦合区的最优参数为直径0.9μm、间隙0.5μm及耦合长度218μm.结果表明,在1.55μm工作波长处分束器可实现偏振分束输出,其带宽约为10 nm,耦合区长度容差为±2μm,直径与间距容差均为-3～2 nm,偏振消光比大于15 dB.

The characteristics of the polarization coupling of two micro/nano optical fibers that are closed to each other were investigated by three dimension full vector beam propagation method （3D FVBPM）. The analytical results of their characteristics of the polarization coupling show that a polarization beam splitter （PBS） based on coupled micro/nano optical fiber can be constructed. Considering the polarization splitting performance of the component, the geometric parameters of the PBS, such as the diameter of micro/nano optical fiber and the gap between them are optimized. The optimal parameters are as follows： the diameter of about 0. 9 /zm, the gap of about 0. 5 Ixm and the length of 218 p^m. Numerical simulations show that we can acquire fabrication tolerances for the polarization splitter at a wavelength of 1 550 nm when the extinction ratio of polarization of both output ports of the splitter are larger than 15 dB, such as a bandwidth of about 10 nm, overlapping length of ±2 μm, and about -3 -2 nm for the diameter and gap respectively.