Fang Liang, Wang Jian
Opt Express. 2018 Jun 11;26(12):15124-15137. doi: 10.1364/OE.26.015124.
We propose and design a new kind of all-fiber polarization beam splitter and rotator (PBS and PBR) based on vector-mode-assisted coupling. By embedding a high-contrast-index ring-core between two cores of the conventional fiber couplers, being a three-core coupling structure, the state of polarization (SOP) of fiber-guided modes can be availably controlled, such as polarization splitting and rotating, by transitional coupling through TM or TE vector mode. Furthermore, the SOP of coupled mode can be rotated with arbitrary angle under different three-core layouts. In particular, by exploiting HE-assisted coupling case, we can realize full-dimensional SOP rotation for arbitrary polarization input. We give the numerical simulation for the proposed all-fiber PBS and PBR, and investigate the corresponding polarization extinction ratio and polarization rotating purity in detail. The calculation results manifest a favorable performance on SOP management of fiber-guided modes. This vector-mode-assisted coupling might be expected to find potential applications in the polarization-based optical signal processing, multiplexing, and sensing system.
我们提出并设计了一种基于矢量模式辅助耦合的新型全光纤偏振分束器和旋转器（PBS和PBR）。通过在传统光纤耦合器的两个纤芯之间嵌入一个高对比度折射率的环形纤芯，形成三纤芯耦合结构，光纤导模的偏振态（SOP）可以通过TM或TE矢量模式的过渡耦合得到有效控制，如偏振分束和旋转。此外，在不同的三纤芯布局下，耦合模的SOP可以旋转任意角度。特别是，通过利用HE辅助耦合情况，我们可以实现对任意偏振输入的全维度SOP旋转。我们对所提出的全光纤PBS和PBR进行了数值模拟，并详细研究了相应的偏振消光比和偏振旋转纯度。计算结果表明在光纤导模的SOP管理方面具有良好的性能。这种矢量模式辅助耦合有望在基于偏振的光信号处理、复用和传感系统中找到潜在应用。
