基于耦合环的主动调Q平滑脉冲光纤激光器  

Actively Q⁃switched Fiber Laser with Smooth Pulse Based on Coupler Ring

作　　者：张东 路桥 李文彩 Zhang Dong;Lu Qiao;Li Wencai(School of Environmental Science and Optoelectronic Technology,University of Science and Technology of China,Hefei 230026,Anhui,China;Anhui Provincial Key Laboratory of Photonic Devices and Materials,Anhui Institute of Optics and Fine Mechanics,Hefei Institutes of Physical Science,Chinese Academy of Sciences,Hefei 230031,Anhui,China;School of Automation,Nanjing University of Information Science and Technology,Nanjing 210044,Jiangsu,China;School of Mathematics and Physics,Anhui Jianzhu University,Hefei 230031,Anhui,China)

机构地区：[1]中国科学技术大学环境科学与光电技术学院,安徽合肥230026 [2]中国科学院合肥物质科学研究院安徽光学精密机械研究所光子器件与材料安徽省重点实验室,安徽合肥230031 [3]南京信息工程大学自动化学院,江苏南京210044 [4]安徽建筑大学数理学院,安徽合肥230031

出　　处：《中国激光》2024年第21期242-248,共7页Chinese Journal of Lasers

基　　金：国家自然科学基金(61805258);江苏省自然科学基金(BK20230418);安徽省自然科学基金(2108085QF284)。

摘　　要：演示了一种脉冲平滑的W量级窄线宽主动调Q光纤激光器。为了提高激光器储能,采用高掺杂的大模场双包层光纤作为增益介质。同时,为了构建适用于高增益腔的高损伤阈值主动调Q开关,利用β-BaB2O4(BBO)晶体的线性电光效应设计了一种新颖的尾纤型强度调制器。进一步地,为了解决Q开关打开过快造成输出脉冲出现多峰的问题,引入光纤耦合环,使得初始信号能量缓慢释放,等效于增加Q开关的上升沿时间。通过这种方法,获得了波形平滑的激光脉冲,并深入分析了脉冲时域演化原理。在5.5 W泵浦功率下,激光器最终实现了平均功率高于1 W、线宽窄至0.08 nm以及脉宽为35 ns的平滑脉冲输出。Objective Utilizing actively Q-switched fiber lasers to generate high-energy narrow-linewidth nanosecond laser pulses is a mainstream technology.Various types of active Q-switches have been developed based on different principles.Among them,fiberpigtailed acousto-optic modulators(AOMs)and electro-optic modulators(EOMs)have garnered wide attention owing to their nanosecond-level switching time and high extinction ratios spanning tens of decibels.However,the output of Q-switched fiber lasers based on fast switches,such as AOMs and EOMs,typically exhibits a typical multipeak structure.Researchers have proposed various methods to address this issue;however,they present certain limitations.Therefore,obtaining high-power narrow-linewidth lasers with smooth pulses from actively Q-switched fiber lasers is crucial.In this study,a novel Q-switch is designed based on the linear electro-optic effect of aβ-BaB2O4(BBO)crystal with a high damage threshold.Moreover,to eliminate the multipeak phenomenon caused by the short rise time of the Q-switch,a fiber coupler is used to form a coupling ring(CR),which enables a gradual release of the initial signal energy and successfully realizes a smooth pulse output.Methods To construct an intensity modulator suitable for high-power lasers,a pair of single-mode fiber collimators(COLs)is used for spatial optical-path coupling.A high-damage-threshold BBO uniaxial crystal is placed between orthogonal polarization devices.The intensity of the transmitted laser can be modulated by applying a periodic half-wave voltage to the BBO crystal.Additionally,to obtain a smooth Q-switched pulse output,a smooth and long-rise waveform is required.The longer the circulation time within the fiber CR,the longer the rise time.However,this implies that the precision of the input pulse segmentation decreases,thereby reducing the smoothness of the rise-time waveform.Therefore,a fiber CR comprising optical coupler is inserted,with the ring length set to 0.5 m.Results and Discussions First,the performance of the c

关 键 词：光纤激光器 调Q 窄线宽 高功率 平滑脉冲 

分 类 号：O436[机械工程—光学工程]