Research Of Low-Loss Coupling Between Anti-Resonant Hollow-Core Fibers And Tapered Solid-Core Fibers

Anti-Resonant Hollow-core fibers(AR-HCFs)are a kind of special micro-structure fibers with hollow-core structure,low dispersion,low nonlinear coefficient.These fibers have wide range of applications of the interaction between light and gas,high energy laser transmission,pulse compression,optical fiber sensing and next-generation optical communication.The normal AR-HCFs mainly includes ice-cream type and non-node type.Accompanied by the deep research of AR-HCFs and the application of all-fiber lasers,it is necessary to deal with the low-loss coupling between AR-HCFs and solid-core fibers.The current low-loss coupling schemes are not suitable for AR-HCFs with special micro-structure.What's more,the coupling efficiency is relatively low.In this paper,a coupling scheme is proposed to change equivalent mode field diameters of output end by tapering solid-core fibers,which uses tapered solid-core fibers inject into the hollow-core structure of AR-HCFs to couple.In this paper,the variation of equivalent mode field diameters of tapered fibers and the factors influencing the coupling between AR-HCFs and solid-core fibers are analyzed.On this basis,the simulation and experiments of the coupling scheme which uses tapered fibers inject into the hollow-core structure of AR-HCFs are researched.The main contents are as follows:1.The development history of photonic crystal fibers based on AR-HCFs is introduced,and the current development situation is expounded.The main application direction of photonic crystal fibers including AR-HCFs is analyzed.Then,the coupling technology and improvement scheme of photonic crystal fibers and solid-core fibers are further combed.2.The several theoretical guiding mechanism models of AR-HCFs are analyzed.The main theory of tapered fibers and Beam Propagation Method(BPM)is introduced.By using BPM,the equivalent mode field diameters of tapered fibers simulation models are analyzed.Then,the intrinsic and non-intrinsic factors which affect the coupling between AR-HCFs and solid-core fibers are analyzed.It is pointed out that the matching of equivalent mode field diameters between these two types fibers is the key to realize low-loss coupling.On this basis,a variety simulation coupling of single-ended,double-ended output without tapering and double-end both tapering between AR-HCFs and solid-core fibers are carried out.The simulation results show that the single-ended coupling efficiency can exceed 94% and the maximum coupling efficiency is 92% on doubled-ended condition when the equivalent mode field diameters are matched,particularly for the ice-cream type AR-HCFs with core diameters of 45?m.3.The experimental research of low-loss coupling between AR-HCFs and tapered solid-core fibers on single-ended condition is carried out.The experimental results show that the single-ended coupling efficiency can exceed 90% for the ice-cream type AR-HCFs with core diameters of 45?m.Meanwhile,the other factors which influence the coupling efficiency are also quantitatively analyzed.4.The experimental research of low-loss coupling between AR-HCFs ant tapered solid-core fibers on double-ended condition is carried out.The coupling between AR-HCFs and solid-core fibers on double-ended output without tapering condition are experimentalized.Meanwhile,the high precision double-ended low-loss coupling systems are built.The experimental results show that the coupling efficiency is up to 85% for the ice-cream type AR-HCFs with core diameters of 45?m.The other factors which influence the double-end coupling efficiency are also quantitatively analyzed.