Study On The Splicing Technology Of Special Fibers And The Related Devices

Photonic crystal fiber (PCF) has been used widely in fiber optical sensing andcommunication field since its emergence owing to many advantages. With thepracticality of PCF, the problem about the fusion-splicing of PCF and single-mode fiber(SMF) needs to be solved. The theoretical analysis, numerical simulation andexperimental study of splice loss are presented in this thesis, and the PCF Fabry-Perotinterferometer based on the PCF fusion-splicing technique is also studied theoreticallyand experimentally. The contents of this thesis are as followings:1. The basic theory of fusion-splicing SMF and PCFs is firstly introduced and thenthe effect of the splice discharge on the PCFs holes structure and the dopant diffusionsof SMF studied in detail. The effects of overlap distance and cutting level of PCFs onthe splice point in manual operation are also described in detail. The relationshipbetween the above mentioned splice parameters and fusion-splicing loss of PCFs isanalyzed and optimized by using numerical analysis and simulation.2. It is analyzed theoretically the effect of the air hole collapse of solid-core PCFson the mode field and coupling loss is studied theoretically for the solid-core PCFs. Thesplice loss can be decreasing when can control the collapse degree of air holes andmatch the mode field of SMF well. Simultaneously, we research the effect of the airhole collapse of hollow-core PCF on the waveguide structure and loss is studiedtheoretically. The lowest splice loss can be achieved when the air holes of hollow-corePCF did not collapse.3. On the basis of analyzed theoretically that a solution for decreasing the spliceloss of the solid-core PCF and hollow-core PCF with SMF is proposed. The splice lossis decreased by filling gas into the air hole of solid core PCF which can control thecollapse degree of air holes. Experimental results show that the lowest splice losses are0.4dB and1.05dB when the filling gas pressures are1.34bar and1.65bar forsolid-core/hollow-core PCFs respectively. For hollow-core PCF we also presentinserting a diameter matched etched SMF into the hollow core PCF that can eliminatingthe effect of the splice point on the mode field propagation is proposed, the feasibility ofwhich is then verified by numerical analysis and the loss is0.4dB.4. A Fabry-Perot interferometer is fabricated in PCF ESM-12-01based on thestudy of PCF fusion-splicing, which is then analyzed theoretically and studied experimentally.(1) The formation and sensing mechanism of the Fabry-Perotinterferometer is verified by theoretical analysis and numerical simulation.(2) Thesensor shows good temperature sensitivity, linearity and stability for a long time at800℃.(3) By coating on the reflect end of the sensor, the signal is enhanced and thetemperature sensitivity is also increased.In conclusion, the solutions for lowering the fusion-splicing loss of solid or hollowcore PCF are proposed and verified by theoretical and experimental study. And the PCFsensing device based on the PCF splice technique is fabricated, enriching anddeveloping the fusion-splicing technique of the PCF and the categories of PCF sensors.