全固态微结构弯曲不敏感型光纤研究

Analysis of All-Solid Microstructured Bend-Insensitive Optical Fiber

提出一种新型弯曲不敏感光纤：在阶跃光纤的包层中引入微结构，排布低折射率介质柱以降低弯曲损耗，通过在纤芯外侧设置低折射率环形区以去除高阶模，通过保持环形区和纤芯的折射率差以保证光纤的低连接损耗。采用有限元法分析了光纤的基模弯曲损耗和高阶模的束缚损耗。采用光束传播法分析了微结构光纤与普通单模光纤的连接损耗。计算结果表明：这种新型光纤的弯曲损耗不仅满足G．657A1标准的要求，且与标准单模光纤的连接损耗小于0．08dB。

A novel bend-insensitive optical fiber is proposed. Low-index rods are included in the cladding to reduce the bending loss, and low refractive index ring surrounding the core is used to remove the higher-order mode. Index- contrast between the core and the low-index ring is conserved to ensure low splicing loss in standard single-mode optical fiber. The bending loss of the fundamental mode and the confinement loss of the higher-order mode are investigated by the finite-element method. The splicing losses between the bend-insensitive optical fiber and the single-mode optical fiber are investigated by the beam propagation method. The results show that the bending loss of the proposed fiber can meet the G. 657 A1 standard and the splicing loss between the bend-insensitive optical fiber and the single-mode optical fiber is less than 0.08 dB.