具有宽带稳定偏振拍长的双折射多孔光纤

A Birefringent Holey Fiber with a Stable Broadband Polarization Beat-Length

为降低偏振拍长对波长变化的敏感性，扩大多孔光纤偏振器件的工作带宽，针对一种包层空气孔呈圆形阵列分布的多孔光纤，应用全矢量有限差分光束传播法分析了不同参数的包层结构对偏振拍长及其相对变化率的影响，通过横向伸缩形变在包层中引入特定的非对称结构，这种方法不仅有效降低了偏振拍长的波长敏感性，而且偏振拍长对这些特定包层结构参数的误差微扰不敏感，在1．2～1．7μm波长范围内，偏振拍长的相对变化率小于±4％，工作带宽达到500nm，同时包层结构几何参数的误差容限达到0．1μm量级，较好地兼顾了偏振拍长的宽带稳定性与多孔光纤工艺制作可行性。

In order to reduce the sensitivity of the polarization beat length with wavelength and expand the operating bandwidth of the polarization device made by the holey fiber, the holey fiber with diamond lattice, the influence of the special holes near the core, the bottom holes and the pitch of diagonal holes on the wavelength sensitivity of polarization beat length are analyzed. The preliminary optimal cladding structure parameters are obtained. The polarization beat length remains stable in a wide wavelength range. The results show that the relative variation of polarization beat length is operating bandwidth can reach 500 nm while the less than ±4% in wavelength range of 1.2-1.7 μm and the error tolerance of optimized geometric parameters is greater than 0.1 9m. The more feasible process structure parameters are provided for drawing the achromatic holey fiber wave plates with broadband.