基于光栅反馈技术的掺铥光纤随机激光器  

Tm^(3+)-doped Fiber Random Laser Based on Fiber Grating Feedback Technology

作　　者：朱德才 胡耀宗 周乐文 黄昌清 董新永 ZHU Decai;HU Yaozong;ZHOU Lewen;HUANG Changqing;DONG Xinyong(School of Information Engineering,Guangdong University of Technology,Guangzhou 510006,China;Guangdong Provincial Key Laboratory of Information Photonics Technology,Guangzhou 510006,China;College of Optical and Electronic Technology,China Jiliang University,Hangzhou 310018,China)

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

出　　处：《光子学报》2022年第11期117-123,共7页Acta Photonica Sinica

基　　金：国家重点研发计划(No.2020YFB805800);国家自然科学基金(Nos.61775204,11974083);广东省引进创新创业团队项目(No.2019ZT08X340);浙江省基础公益研究计划(No.LGG19A040001)。

摘　　要：提出一种基于光栅反馈技术的掺铥光纤随机激光器。激光器采用半开腔设计,封闭端采用中心波长为1 940 nm的高反射率光纤光栅为激光器系统提供强反馈,增益介质采用1.5 m长的掺铥光纤,泵浦源采用793 nm半导体激光器,开放端采用光纤随机光栅提供随机分布反馈。该光纤随机光栅由飞秒激光逐点刻写技术制备,在10 cm单模光纤上刻写超过6 000个间距随机分布的折射率畸变点,以增强光纤的后向瑞利散射效应。实验测得中心波长为1 940 nm的随机激光输出,其泵浦阈值为2.33 W,在3.8 W泵浦功率下的输出功率为57 mW,光信噪比达56 dB。输出激光在1 h内的波长偏移量小于0.1 nm,功率变化约0.26 dB,具有良好的稳定性。Random Fiber Lasers(RFLs) based on random distributed feedback can operate without a precise resonant cavity,leading to the advantages of simple structure and low production cost.In previous work,random fiber lasers operating in the band of 1.0~1.6 μm have been widely investigated.However,limited by the high transmission loss of ~30 dB/km and the weak Rayleigh scattering efficiency in normal silica fibers,random fiber lasers operating in the band of 2 μm are rarely reported.It’s of great fundamental interest to push the random fiber lasers to 2 μm mid-infrared band for their potential applications in the fields including medical surgery,nonlinear optics,material processing,and remote sensing.In this work,a random fiber laser operating in 2 μm band is developed by using a 1.5 m long thulium-doped fiber as the gain medium and a fiber random grating for random distributed feedback with enhanced Rayleigh scattering efficiency.The proposed random fiber laser adopts the half-open cavity design by using a high reflectivity fiber Bragg grating with a central wavelength of 1 940 nm to provide strong feedback to the laser system.A793 nm semiconductor laser is employed as the pump laser source.The fiber random grating containing over 6 000 refractive index distortion spots was inscribed point by point along with a 10 cm long singlemode fiber by using a Ti:sapphire femtosecond regenerative amplifier with an operation wavelength of800 nm,a repetition rate of 100 Hz and a pulse duration of 80 fs.The neighboring refractive index distortion points were spaced at a random distance between 7.5 and 12.5 μm.Experimental results show that random laser output at the wavelength of 1 940 nm is achieved with a relatively low threshold power of2.33 W.Benefit from the enhanced Rayleigh scattering efficiency of the fiber random grating,the pump threshold of the random fiber laser is much lower than that of the previously reported random fiber laser in2 μm region.With increasing the pump power,an output power of the random fiber lase

关 键 词：光纤激光器 随机激光器 掺铥光纤 光纤光栅 光栅反馈 

分 类 号：TN248.1[电子电信—物理电子学]