724 W,0.9 mJ,227 fs四通道相干合成超快光纤激光系统(特邀)  

724 W,0.9 mJ,227 fs Four-Channel Coherently Combined Ultrafast Fiber Laser System(Invited)

作　　者：王志浩 彭双喜 徐浩 李政言 张庆斌 陆培祥 Wang Zhihao;Peng Shuangxi;Xu Hao;Li Zhengyan;Zhang Qingbin;Lu Peixiang(Wuhan National Laboratory for Optoelectronics and School of Physics,Huazhong University of Science and Technology,Wuhan 430074,Hubei,China;School of Optical and Electronic Information,Huazhong University of Science and Technology,Wuhan 430074,Hubei,China;Optics Valley Laboratory,Wuhan 430074,Hubei,China)

机构地区：[1]华中科技大学武汉光电国家研究中心与物理学院,湖北武汉430074 [2]华中科技大学光学与电子信息学院,湖北武汉430074 [3]湖北光谷实验室,湖北武汉430074

出　　处：《光学学报》2024年第17期283-290,共8页Acta Optica Sinica

基　　金：国家自然科学基金(92150106,12021004,11934006);湖北省重大项目(JD)(203BAA015);光谷实验室创新项目(OVL2021ZD001);华中科技大学交叉研究支持计划(2023JCYJ041)。

摘　　要：报道了一种基于四通道光纤放大器相干光束合成的高功率飞秒激光系统。每个通道均采用大模场棒状光子晶体光纤,平均功率达到220 W。通过稳定的主动相位锁定技术,压缩后的激光系统在800 kHz的重复频率下实现了724 W的平均功率和0.9 mJ的单脉冲能量。合成后的激光保持了良好的光束质量和功率稳定性,合束光斑的光束质量因子M^(2)<1.25,功率波动的均方根误差为0.59%。此外,通过优化各通道放大器的增益并测量分析压缩后脉冲的时域特性,实现了对放大前脉冲的精确色散预补偿。本系统在没有使用脉冲整形或者光谱调制的情况下,实现了脉冲宽度从445 fs到227 fs的优化。Objective High-average-power and high-repetition-rate femtosecond fiber lasers are widely used in industrial and scientific domains.However,the presence of excessive nonlinearity and transverse mode instability poses a constraint on further scaling of energy and power within the fiber lasers.Coherent beam combination(CBC)has risen as a viable solution to the constraint,enabling the extension of average power and pulse energy limits while preserving beam quality.Under ideal conditions,the laser power and energy of the combined beam from N channels can reach N times that of a single amplifier.However,in real-world applications,variations in beam quality and discrepancies in the spatiotemporal properties of the beams result in power losses during the combining process.These losses are quantified by the combining efficiency.Recently,an average power of 1 kW with a pulse energy of 1 mJ and an average power of 1 kW with a single pulse energy of 10 mJ are achieved through 8-channel and 16-channel fiber laser CBC,respectively.Yet,the proliferation of combination paths not only increases system complexity but also affects stability.Moreover,due to gain narrowing and incomplete dispersion compensation,compressed pulses typically exceed 300 fs,presenting hurdles in achieving Fourier limit pulse duration.Although methods such as spectral shaping and post-compression can further shorten the pulse duration,these methods undoubtedly further increase the complexity and operational difficulty of the system.Hence,we focus on reducing the number of combination paths and improving dispersion compensation to achieve clean ultrashort femtosecond pulses while maintaining the existing power level.Methods To streamline the number of combination paths,enhancing the power of a single amplifier is crucial.By boosting the power of a single amplifier beyond 200 W,the number of required combination channels can be reduced by a factor of 2 to 3.An ultrafast femtosecond fiber system comprising four coherently combined large mode-area rod-type ph

关 键 词：超快光纤激光器 相干光束合成 啁啾脉冲放大 色散补偿 

分 类 号：TN248[电子电信—物理电子学]