0.59mJ单频掺Yb^(3+)百纳秒脉冲全光纤激光器  

0.59-mJ Single-Frequency Yb^(3+)-Doped Hundred-Nanosecond Pulsed All-Fiber Laser

作　　者：田浩[1,2] 史朝督 付士杰 盛泉[1,2] 孙帅[1,2] 张帅 张钧翔[1,2] 石争 蒋沛恒 史伟 姚建铨 Tian Hao;Shi Chaodu;Fu Shijie;Sheng Quan;Sun Shuai;Zhang Shuai;Zhang Junxiang;Shi Zheng;Jiang Peiheng;Shi Wei;Yao Jianquan(School of Precision Instrument and Optoelectronics Engineering,Tianjin University,Tianjin 300072,China;Key Laboratory of Optoelectronic Information Technology(Ministry of Education),Tianjin University,Tianjin 300072,China)

机构地区：[1]天津大学精密仪器与光电子工程学院,天津300072 [2]天津大学光电信息技术教育部重点实验室,天津300072

出　　处：《中国激光》2022年第13期29-34,共6页Chinese Journal of Lasers

基　　金：国家自然科学基金(62075159,61975146,62105240)。

摘　　要：报道了基于混合增益光纤实现的1064 nm高能量单频掺Yb^(3+)百纳秒脉冲全光纤激光器。当主放大级的泵浦功率为13 W时,获得了最大0.59 mJ的脉冲能量,重复频率为5 kHz,脉冲宽度为104 ns。主放大级采用芯径分别为35μm和50μm的掺Yb^(3+)光纤级联作为增益介质,以此来提高受激布里渊散射阈值和激光信噪比。为了保证转换效率,对有源光纤长度和盘绕方式进行了优化,实现了较好的光束质量,最大脉冲能量时光束质量为1.50,光谱线宽为40 MHz。Objective Progress on high-energy hundreds-ns all-fiber single-frequency fiber master-oscillator-power-amplifier(MOPA)is mainly constrained by the stimulated Brillouin scattering(SBS)effect.The SBS can be generally suppressed by using large-mode-area active fibers with high dopant concentration so that short fiber length is allowed for power scaling.Whereas the insufficient extraction of population inversion due to the limited seed power induces a significant part of amplified spontaneous emission(ASE),which degrades the spectral purity.To avoid this when increasing the SBS threshold of the pulsed single-frequency laser,a fiber amplification scheme based on a hybrid active fiber structure is proposed here to achieve a high energy output.A piece of heavily Yb^(3+)-doped phosphosilicate fiber with a large core diameter is spliced after a piece of Yb^(3+)-doped silica fiber with a smaller core diameter.The difference in active fiber size introduces the loss to the reversed Stokes light,which is similar to the operating principle of an outstanding tapered fiber,thereby increasing the threshold of SBS while avoiding the complicated fabrication process.The signal which is pre-amplified by the low Yb^(3+)-doped silica fiber can effectively extract the population inversion in the phosphosilicate fiber,which exhibits the benefits on ASE suppression and efficiency improvement.Methods The 1064.44 nm continuous-wave(CW)laser with a power of 76 mW is modulated by an electro-optic intensity modulator(EOIM)to become a pulsed laser source with a pulse duration of 100 ns.A single-frequency pulsed laser source with an average power of 1 mW is obtained after two-stage Yb^(3+)-doped fiber core-pumped pre-amplification and an acousto-optic modulator(AOM)synchronized with the EOIM.The average power of the pulsed laser source is increased to 120 mW corresponding to the pulse energy of 0.024 mJ after two-stage Yb^(3+)-doped fiber cladding-pumped pre-amplification.In the power amplifier,a hybrid active fiber structure,consisting of a 30

关 键 词：激光器 光纤激光器 脉冲激光器 激光放大器 受激布里渊散射 

分 类 号：TN248[电子电信—物理电子学]