高精度同步飞秒和皮秒脉冲产生技术  

High-Precision Synchronous Femtosecond and Picosecond Pulse Generation

作　　者：钱富琛 郭政儒 董文乾 胡晓蕾 陈飞[1] 郝强[1] 曾和平[2,3] Qian Fuchen;Guo Zhengru;Dong Wenqian;Hu Xiaolei;Chen Fei;Hao Qiang;Zeng Heping(School of Optical-Electrical and Computer Engineering University of Shanghai for Science and Technology,Shanghai 200093,China;State Key Laboratory of Precision Spectroscopy,East China Normal University,Shanghai,200062,China;Jinan Institute of Quantum Technology,Jinan,Shandong 250101,China)

机构地区：[1]上海理工大学光电信息与计算机工程学院,上海200093 [2]华东师范大学精密光谱科学与技术国家重点实验室,上海200062 [3]济南量子技术研究院,山东济南250101

出　　处：《中国激光》2020年第10期1-6,共6页Chinese Journal of Lasers

基　　金：国家重点研发计划(2018YFB0407100)。

摘　　要：设计了一款重复频率精确锁定的飞秒脉冲和皮秒脉冲双路输出光纤激光器。该激光器采用输出为近傅里叶变换极限的皮秒脉冲作为种子源,其脉冲宽度为21 ps,重复频率为40 MHz。该种子脉冲经1∶1分束后,分别注入飞秒和皮秒脉冲放大链路中。通过有效管理脉冲放大过程中的非线性和色散,实现了宽带光谱飞秒脉冲和窄带光谱皮秒脉冲的同步输出。其中,飞秒脉冲放大链路是将皮秒种子脉冲先经过单模光纤功率放大器,而后在50 m保偏单模光纤中利用自相位调制效应进行光谱展宽,光谱展宽至6.12 nm;进一步采用光栅对去啁啾后,得到了脉冲宽度为483 fs、平均功率为210 mW的飞秒脉冲输出。皮秒脉冲放大链路的皮秒种子脉冲经过功率预放大、脉冲选单至10 MHz后,由200/40光子晶体光纤主放大器进行功率提升,得到了脉冲宽度为25 ps、单脉冲能量为1.4μJ、光谱宽度为0.86 nm的皮秒脉冲输出。此外,通过采用压电陶瓷精确控制和步进电机范围控制相结合的方式,实现了对皮秒种子源谐振腔重复频率的长时间精确锁定。激光器开启并达到热平衡后,8 h测量时间内重复频率峰峰值抖动小于3 mHz,标准偏差为0.31 mHz。We demonstrate a dual-output ultrashort pulse fiber laser with their repetition rate precisely locked.This laser source employs a mode-locked picosecond laser capable of delivering near transform-limited pulses with 21 ps duration at a repetition rate of 40 MHz.After the seed pulse is split 1∶1,it is injected into the femtosecond and picosecond pulse amplification links respectively.By effectively managing the nonlinearity and dispersion in the pulse amplification process,the synchronous output of broadband spectral femtosecond pulse and narrowband spectral picosecond pulse is realized.In the path of femtosecond pulses,a length of 50 m polarization-maintaining single-mode fiber is used to promote the spectral broadening of amplified pulses,and its spectral width is broadened to 6.12 nm owing to the effect of self-phase modulation.Then,a pair of bulk gratings is applied to de-chirp the pulse to 483 fs duration with 210 mW average power.For the other optical path,the seed pulses are firstly pre-amplified and then selected to 10 MHz repetition rate.The 200/40 photonic crystal fiber acts as the gain fiber in main amplifier to further boost the pulses,generating 25 ps pulse duration with 1.4μJ energy and 0.86 nm spectral width.In addition,the repetition rate long-term stabilization is realized by the combination of piezoelectric translator for precise control and stepping motor for range control.When laser system warms up,the peak-to-peak fluctuation of pulse repetition rate is less than 3 mHz within 8 h,and the corresponding standard deviation is calculated to be 0.31 mHz.

关 键 词：激光器 光纤激光器 超短脉冲同步 锁模激光器 非线性效应 

分 类 号：O436[机械工程—光学工程]