Qin Yan, Yang Huajun, Jiang Ping, Gui Fengji, Caiyang Weinan, Cao Biao
Appl Opt. 2018 May 10;57(14):3976-3982. doi: 10.1364/AO.57.003976.
In this paper, an asymmetric large-mode-area photonic crystal fiber (LMA-PCF) with low bending loss at a smaller bending radius is designed. The finite-element method with a perfectly matched layer boundary is used to analyze the performance of the PCF. To achieve LMA-PCF with low bending loss, the air holes with double lattice constants and different sizes at the core are designed. Numerical results show that this structure can achieve low bending loss and LMA with a smaller bending radius at the wavelength of 1.55 μm. The effective mode area of the fundamental mode is larger than 1000 μm when the bending radius is ≥10 cm. The bending loss of the fundamental mode is just 0.0113 dB/m, and the difference between the fundamental and high-order modes of the bending loss is larger than 10 when the bending radius is 10 cm. Simulation results show this novel PCF can achieve LMA and have effective single-mode operation when the bending orientation angle ranges in ±110°. This novel photonic crystal has potential application in high-power fiber lasers.
本文设计了一种在较小弯曲半径下具有低弯曲损耗的非对称大模场面积光子晶体光纤（LMA - PCF）。采用具有完全匹配层边界的有限元方法来分析光子晶体光纤的性能。为实现具有低弯曲损耗的LMA - PCF，在纤芯处设计了具有双晶格常数和不同尺寸的气孔。数值结果表明，该结构在1.55μm波长下能在较小弯曲半径下实现低弯曲损耗和大模场面积。当弯曲半径≥10cm时，基模的有效模场面积大于1000μm²。当弯曲半径为10cm时，基模的弯曲损耗仅为0.0113dB/m，且基模与高阶模弯曲损耗的差值大于10。仿真结果表明，当弯曲取向角在±110°范围内时，这种新型光子晶体光纤能够实现大模场面积并具有有效的单模工作。这种新型光子晶体在高功率光纤激光器中具有潜在应用。
