Controlling of symmetric and asymmetric mode coupling in long-period fiber gratings singe-side induced by long-pulse CO2 laser |
| |
| Authors: | Xuesong Liu Li Zhan Shouyu Luo Yuxing Xia |
| |
| Affiliation: | a Department of Physics, State Key Laboratory on Fiber-optic Local Area Networks and Advanced Optical Communication Systems, Shanghai Jiao Tong University, Shanghai, 200240, Chinab Laboratory of Photonic Information Technology, School of Information and Photoelectronic Science & Engineering, South China Normal University, Guangzhou, China |
| |
| Abstract: | We report a simple fabricating approach to control the mode couplings in long-period fiber gratings (LPFGs) through side exposing fiber to long-pulse-10.6-μm laser from a cheap, internally modulated CO2 tube. By tuning focused-spot size on fibers, not only circularly symmetric mode coupling but also asymmetric mode couplings can be effectively achieved. Simulation of mode profiles in grating cross-section with Finite Element Method (FEM), and LPFG-cladding etching experiment with hydrofluoric acid (HF), support our explanation that asymmetric mode coupling in LPFGs depends on local refractive-index (RI) change within an azimuthally thin cladding layer, resulted from large-spot method induced deep melt flow on fiber surface during CO2 laser irradiation. |
| |
| Keywords: | Long period fiber gratings Asymmetric mode coupling Melt flow Finite Element Method Etching |
| 本文献已被 ScienceDirect 等数据库收录！ |
|
