Study On Functional Devices Of Photonic Crystal Fibers

In recent years, photonic crystal fibers(PCFs) have attracted considerable interest due to their unique properties and potential applications. The work in this report was supported by the National basic research program of China (Innovation and basic research of photoelectron functional devices based on microstructured optical fibers, Grand No. 2003CB314906), the National Science Foundation Project of China (Study on the novel laser based on the photonic crystal fibers infused by quantum dot material, Grand No. 10674074), the China Postdoctoral Science Foundation (Study on coupling mechanism of mulit-core photonic bandgap fibers and its applications in photonic devices,Grand No. 20060400687), and so on. In this report, we firstly review the progress in PCFs. Then we mainly focus on the research of devices based on PCFs, such as the multi-core PCFs coupler, the fiber grating inscribed in PCFs, and nonlinear effect in PCFs. The contents are listed as follows:1. A novel Photonic Crystal Fiber (PCF) coupler with single-polarization single-mode (SPSM) feature is theoretically proposed. The SPSM coupling range is over 200nm for a variety of parameters.2 . We have theoretically and experimentally investigated the coupling in dual-core photonic bandgap fibers (PBGFs). The novel coupling characteristics in dual-core hollow-core PBGFs and dual-core all-solid PBGFs, such as such as maxima and minima in coupling length, complete decoupling of the cores, are theoretically investigated. The dual-core all-solid PBGFs are fabricated by using a modified stack-and-draw process and their coupling length are measured. The experimental results show good qualitative agreement with the numerical results. 3. We theoretically propose directional couplers operated by resonant coupling in all-solid photonic bandgap fibers structure. The resonant effect induced by the avoided crossing between core-guided supermodes and defect-guided modes significant decreases the coupling length in this structure. The directional couplers have potential application in realizing integrating all-fiber communication devices.4.The fiber Bragg gratings are inscribed in the index-guided PCFs and all-solid PBGFs, and the long-period gratings are induced by periodical microbend. The resonant properties in these gratings are theoretically and experimentally investigated.5.The software for sovling nonlinear Schr?dinger equations are developed based on the split-step Fourier method. The propagation and the pulse trapping process of ultrashort pulse in liquid-filling PBGFs are investigated by using this software.6. The compact supercontinuum source are realized by using a passively Q-switched Nd:YAG laser and an endlessly single mode PCF. The supercontinuum spectrum extending from 500 nm to beyond 1750 nm is demonstrated.