Kagome结构空芯光子晶体光纤纤芯参数对传输特性的影响

Changes of propagation characteristics with core parameters in kagome-structured hollow-core photonic crystal fibers

应用全矢量有限元方法,研究大间距Kagome结构空芯光子晶体光纤中纤芯的大小、形状与壁厚对光纤传输损耗谱的影响。结果表明,某些纤芯尺寸会造成包层中的结构缺陷,易使纤芯基模、表面模及包层模之间发生能量耦合,产生较大损耗。而纤芯形状与壁厚的改变会引起表面模式的变化,从而影响发生在基模与表面模之间反向耦合的位置和强度,使光纤传输频带变窄和损耗变大。据此,提出Kagome结构光纤的纤芯设计思路,即纤芯的大小应使包层保持完整的微结构,纤芯形状应与包层中的单元微结构相楔合,纤芯壁厚应与包层中玻璃支柱的宽度相同。

Based on all-vector finite element method,general features of the loss spectrum of large-pitch kagome lattice hollow-core photonic crystal fiber（HC-PCF） are exhibited by investigating the effects of the core size,core shape and core-cladding boundary width on the guidance properties of the fiber.The numerical simulations show that the operational bandwidth of the fiber is drastically affected by improper core design parameters which cause the interaction among the fundamental core modes,surface modes and cladding modes.Therefore,the design of large-pitch kagome lattice HC-PCF with low loss and broad bandwidth should satisfy these conditions： the core size maintains the complete micro-structures of the cladding,the core shape matches the micro-structure of the cladding cells,and the core-cladding boundary width is equal to the glass struts width of the cladding.