Transmission Simulation Of Hollow-Core Photonic Bandgap Fiber And Its Arc Fusion Splice With Single-Mode Fiber

Photonic crystal fiber(PCF)is a new class of optical fiber and has attracted great attention with its various novel optical characteristics due to the flexible design on structure.With the continuous complementation of the theory and the gradual improvement in fabrication,PCFs are increasingly rich in types and widely used.In order to play a better role in fiber networks,PCFs often need to fuse with other optical fibers,such as single-mode fiber(SMF).In this paper,theoretical and experimental investigations are carried out for the fusion splice between hollow-core photonic bandgap fiber(HC-PBGF)and conventional fiber.The main results are as follows:(1)In view of the fact that HC-PBGF will experience different degrees of air hole collapse in the fusion process,the light transmission in HC-PBGF is simulated numerically using the plane wave expansion method.For HC-PBGF with the design wavelength of 780nm/800nm,it is found that when there is no collapse(d/?=1),the bandgap is the largest and the corresponding operating wavelength range is the widest(652nm<?<958nm);with the increasing degree of air hole collapse,the bandgap width becomes narrower and the number of bandgap increases,which means that the corresponding operating wavelength range moves towards longer wavelengths and the ranges become narrower and are more separated.When d/?=0.94,light with ?=780nm/800nm cannot propagate as the core mode in the fiber.The simulation results have some instructive significance for the explanation of splice loss at different collapse degrees.(2)Arc fusion splicer is used to splice both ends of HC-PBGF with SMF.Firstly,the factors affecting splice loss of HC-PBGF are analyzed theoretically.Then,the main parameters,such as offset,gap,overlap,discharge intensity and discharge time,are optimized to realize the low-loss splice between HC-PBGF(HC-800-02)and SMF(780-HP).Finally,an HC-PBGF-based on-line fiber cavity with a length of approximately 1m is demonstrated,with a total loss of 2.59dB.