基于随机光栅的掺铥光纤随机激光器研究  

Thulium-doped Fiber Random Laser Based on Random Grating

作　　者：胡耀宗 朱德才 黄昌清 董新永 Hu Yaozong;Zhu Decai;Huang Changqing;Dong Xinyong(School of Information Engineering,Guangdong University of Technology,Guangzhou 510006,Guangdong,China;Guangdong Provincial Key Laboratory of Information Photonics Technology,Guangzhou 510006,Guangdong,China;College of Optical and Electronic Technology,China Jiliang University,Hangzhou 310018,Zhejiang,China)

机构地区：[1]广东工业大学信息工程学院,广东广州510006 [2]广东省信息光子技术重点实验室,广东广州510006 [3]中国计量大学光学与电子科技学院,浙江杭州310018

出　　处：《中国激光》2023年第2期9-14,共6页Chinese Journal of Lasers

基　　金：国家重点研发计划(2020YFB805804);国家自然科学基金(61775204,11974083);广东省引进创新创业团队项目(2019ZT08X340);浙江省基础公益研究计划项目(LGG19A040001)。

摘　　要：采用能增强瑞利散射效率的光纤随机光栅作为掺铥光纤随机激光器的随机分布反馈介质,光纤环镜下激光器形成半开腔结构,在793nm半导体激光器泵浦下,实现了波长为1951nm的单波长随机激光输出。激光器的泵浦阈值功率为2.1W,比已报道的相同泵浦波长的掺铥光纤随机激光器的阈值低40%。在泵浦功率为6W时,获得的激光输出功率为142.9mW,边模抑制比为43dB,输出激光在1h内的波长偏移量小于0.1nm,功率波动小于3.7mW,具有良好的稳定性。Objective The 2 μm wavelength band is an eye-safe optical band that contains the absorption lines of water molecules and many atmospheric molecules as well as the spectrum windows for atmospheric communications. Therefore, fiber lasers in the 2-μm-band have been widely studied for their potential applications in fields such as lidar, laser ranging, and surgery. Currently, random fiber lasers(RFLs) have attracted extensive research attention owing to their simple structure and low spatial/temporal coherence properties. These fibers usually utilize back Rayleigh scattering as the random feedback mechanism, combined with the distributed Raman or Brillouin gain in the fiber, to generate random lasers in a long single-mode fiber. However, the Rayleigh scattering intensity of the single-mode fiber is inversely proportional to the fourth power of the wavelength, and the transmission loss is as high as 30 dB/km at 2 μm. Compared with the common RFLs operated at 1. 0-1. 5 μm, RFLs operated within the 2-μm-band are rarely reported, as they are highly difficult to realize. In this work, an RFL operated in a 2 μm region is demonstrated using a thulium-doped fiber as the gain medium and a random fiber grating for random distributed feedback with enhanced Rayleigh scattering efficiency. A laser output of wavelength 1951 nm is achieved with a relatively low pump threshold of 2. 1 W.Methods The proposed RFL is formed using a 793 nm pump laser, 793 nm/2000 nm wavelength-division multiplexer,fiber loop mirror, 1. 5-m-long thulium-doped fiber, and random fiber grating. The random fiber grating containing over six thousand index modulation points along a 10-cm-long single-mode fiber is inscribed using a femtosecond Ti: sapphire regenerative amplifier, which is operated at a wavelength of 800 nm with a repetition rate of 100 Hz and a pulse duration of 80 fs. The neighboring refractive index modulation points are spaced at random distances between 7. 5 μm and 12. 5 μm.The random fiber grating provides an enhanced backward Rayl

关 键 词：激光器 随机激光器 瑞利散射 掺铥光纤激光器 光纤随机光栅 光纤环镜 

分 类 号：TN248.1[电子电信—物理电子学]