In this paper, a simple structure dual-core photonic crystal fiber (SS-DC-PCF) polarization beam splitter (PBS) based on the surface plasmon resonance (SPR) effect and symmetric dual-core coupling mode theory is proposed. For the proposed SS-DC-PCF-1 PBS, the coupling lengths (CLs) and coupling length ratio (CLR) are analyzed, and the variations of the normalized output powers with the propagation length are investigated for the chosen wavelengths 1.434, 1.451, and 1.469 µm. The extinction ratio in cores A and B are compared at the three splitting lengths (SLs) 170, 173, and 176 µm. When the optimal SL is 176 µm, the splitting bandwidth (SB) is 255 nm (1.437–1.692 µm), and the insertion loss (IL) is less than 0.043 dB. The regulations of the CLs and CLR with the change of the structure parameters are analyzed. For the proposed SS-DC-PCF-2 PBS, the optimal SL is 232 µm, the SB is 201 nm (1.249–1.450 µm), and the IL is less than 0.042 dB. Finally, it is demonstrated that the total SB of the proposed SS-DC-PCF-1 PBS and SS-DC-PCF-2 PBS is 443 nm (1.249–1.692 µm), which can cover the ${\rm{O}} + {\rm{E}} + {\rm{S}} + {\rm{C}} + {\rm{L}} + {\rm{U}}$ band, even if the gold film thickness changes by ${{\pm}}\;{{1}}\;{\rm{nm}}$. The proposed SS-DC-PCF PBS has excellent performances, such as ultrashort SL, ultrawide SB, ultralow IL, and good error-tolerance rate. It will have important applications in all-fiber optical systems.

中文翻译：

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基于表面等离子体共振效应的覆盖O+E+S+C+L+U波段的简单结构双芯光子晶体光纤偏振分束器

本文基于表面等离子体共振（SPR）效应和对称双芯耦合模式理论，提出了一种结构简单的双芯光子晶体光纤（SS-DC-PCF）偏振分束器（PBS）。对于所提出的 SS-DC-PCF-1 PBS，分析了耦合长度 (CLs) 和耦合长度比 (CLR)，并针对所选波长 1.434、1.451、研究了归一化输出功率随传播长度的变化。和 1.469 微米。在三个分裂长度 (SL) 170、173 和 176 µm 下比较纤芯 A 和 B 的消光比。当最佳SL为176 µm时，分裂带宽(SB)为255 nm (1.437–1.692 µm)，插入损耗(IL)小于0.043 dB。分析了CLs和CLR随结构参数变化的规律。对于提议的 SS-DC-PCF-2 PBS，最佳 SL 为 232 µm，SB 为 201 nm (1.249–1.450 µm)，IL 小于 0.042 dB。最后，证明所提出的 SS-DC-PCF-1 PBS 和 SS-DC-PCF-2 PBS 的总 SB 为 443 nm (1.249–1.692 µm)，可以覆盖${\rm{O}} + {\rm{E}} + {\rm{S}} + {\rm{C}} + {\rm{L}} + {\rm{U}}$波段，即使金膜厚度变化${{\pm}}\;{{1}}\;{\rm{nm}}$。所提出的 SS-DC-PCF PBS 具有优异的性能，如超短 SL、超宽 SB、超低 IL 和良好的容错率。它将在全光纤光学系统中具有重要的应用。