飞秒激光直写高反射率中红外光纤布拉格光栅  

High Reflectivity Mid-Infrared Fiber Bragg Grating by Femtosecond Laser Direct Inscription Method

作　　者：熊贤伟 陈胜平[2] 朱宏田 王金涛 王金章[1] 郭春雨[1] 闫培光[1] 阮双琛[1,3] Xiong Xianwei;Chen Shengping;Zhu Hongtian;Wang Jintao;Wang Jinzhang;Guo Chunyu;Yan Peiguang;Ruan Shuangchen(Shenzhen Key Laboratory of Laser Engineering,College of Physics and Optoelectronic Engineering,Shenzhen University,Shenzhen,Guangdong 518060,China;College of Advanced Interdisciplinary Studies,National University of Defense Technology,Changsha,Hunan 410073,China;Shenzhen Technology University,Shenzhen,Guangdong 518118,China)

机构地区：[1]深圳大学物理与光电工程学院深圳市激光工程重点实验室,广东深圳518060 [2]国防科技大学前沿交叉学科学院,湖南长沙410073 [3]深圳技术大学,广东深圳518118

出　　处：《中国激光》2022年第1期165-170,共6页Chinese Journal of Lasers

基　　金：国家自然科学基金(61775146,61935014,12074264);深圳市科技计划项目(JCYJ20190808160205460,CJGJZD20200617103003009)。

摘　　要：采用飞秒激光逐线直写法,在氟化物光纤中制备出了窄带宽、高反射率的中红外光纤光栅,其中心波长为2964.34 nm, 3 dB带宽为1.24 nm,反射率高达99.27%。该工作有利于构建"全光纤化"中红外光纤激光器,对推动国内中红外光纤激光器核心器件的全自主化具有重要意义。Objective Mid-infrared fiber lasers have attracted much attention due to high beam quality,high photoelectric conversion efficiency,excellent heat dissipation performance,and prospect of all-optical fibers.They have important applications in ranging,remote sensing,medical and health care,absorption spectroscopy,atmospheric communication,polymer materials processing,infrared countermeasures,and basic science.A fluoride fiber with a low phonon energy and a low transmission loss is usually chosen as the medium for producing and conducting a midinfrared laser.The structure of the space cavity mirror laser has such problems as low coupling efficiency,poor robustness,and easy deliquescence of fluoride fiber end faces.A fiber Bragg grating(FBG)based on fluoride fibers can be used to construct all-fiber lasers,which can effectively solve the above problems.However,the preparation of a mid-infrared fluoride fiber Bragg grating has not been reported in China.It is urgent to study the preparation technology of this key device.In this work,a mid-infrared FBG with a central wavelength of 2964.34 nm and a reflectivity of 99.27%is directly prepared in a fluoride fiber by femtosecond laser line-by-line direct writing method.This work is helpful to improve the operation stability,reliability and miniaturization of a mid-infrared fiber laser,and promote the application of corresponding mid-infrared fiber laser technologies.Methods In this paper,an FBG is prepared by femtosecond laser direct inscription method,and a 513 nm femtosecond laser is selected as the source.The fiber moves uniformly through a high precision three-dimensional displacement platform.The FBG testing device consists of a supercontinuum source,a coupled lens,and a spectrometer.The supercontinuum source(0.5-3.1μm)is coupled to a ZBLAN fiber with an FBG through a pair of coupling lenses(lens material of CaF_(2),focal length f=15 mm),and the end is directly connected to the spectrometer for transmission spectral testing.By comparing various preparation methods of

关 键 词：激光技术 光纤布拉格光栅 光纤激光器 中红外激光器 氟化物光纤 

分 类 号：O436[机械工程—光学工程]