Study On Pressure-assisted Post-processing Technique Of Photonic Crystal Fiber

Photonic crystal fibers （PCFs） receive more and more attention in recent yearsowing to its unique optical characteristics. The post-processing technique of PCFs is toobtain fiber with special structural parameters N₂post-modifying its structure. Theunique characteristics of PCFs with the flexible post-processing technique enable it tobe used for optical system, which cannot be realized only N₂common single mode fiber（SMF）.As one of the post-processing techniques of PCFs developed in recent years, airhole collapsing is an important technique for further application of the potential value ofPCFs. Base on such a technique with pressure-assisted, the low loss fusion splicingbetween PCFs and SMF and selective air hole collapsing are studied in this thesis andthe main contents are as followings:1. The characteristics and application of PCFs and the problems of application, andthe development of the fusion splicing between PCFs and SMF with low loss andselective air hole collapsing are introduced in detail.2. The loss caused N₂core offset, optical field mismatch, air hole collapsing andreflection at the fusion splicing joint between PCFs and SMF are analyzed theoretically,which provide theory basis for lowering the fusion splicing loss of PCFs and SMF.3. The solutions for lowering the splicing loss between both solid core and hollowcore PCFs with SMF are proposed in this thesis, and the main idea is controlling the airhole collapsing N₂inflating N2into air holes of PCFs. Experimental results show thatsplicing loss of⁰.4dB can be achieved when the pressure is1.34bar for the solid corePCF （ESM-12-01）/SMF while¹.05dB can be achieved when the air pressure is1.65bar for the hollow core PCF （HC-1550-02）/SMF.4. Based on the selective air hole collapsing, pressure-assisted post-processingtechnique of PCFs is studied and primary experiment is achieved in this paper.In conclusion, the project is based on the air hole collapsing assisted N₂pressuretechnique. The splicing loss of PCFs/SMF is analyzed theoretically, after that thesolutions for lowering the loss between two kinds of PCFs and SMF. At last theselective air hole collapsing is studied experimentally in order to make some fiberdevices with special characteristics.