针对精密测量的实际应用需求,开发了具有6 MHz重复频率调谐范围的掺镱锁模光纤激光器.该光纤激光器利用啁啾光纤光栅实现色散补偿,可以实现不同色散域的锁模.实验中,系统研究了不同腔内净色散对锁模激光器输出特性和稳定性的影响,发现当具有一定负腔内净色散时,在不同的重复频率下都可以输出相同的光谱,同时输出光谱具有较好的高斯型.根据以上研究,特殊设计了稳定的简化腔结构和空间延迟线,同时优化了腔参数,保证了大范围的重复频率调谐和稳定的锁模运转.当中心重复频率为26 MHz时,调谐比率达到23％.激光器稳定输出平均功率为3.23 mW的飞秒激光脉冲,去啁啾后脉冲宽度为347 fs.基于此,将光纤锁模激光器重复频率锁定于铷原子钟,在1s的平均时间内获得了2×10-10的艾伦方差.“,”For the precise measurement,a femtosecond mode-locked Yb-doped fiber laser with a 6 MHz repetition rate tuning range at a fundamental repetition rate of 26 MHz was reported,corresponding to 23％ tuning ratio.With chirped fiber Bragg grating,the mode-locked fiber laser could run at different dispersion regimes.The influence of the net cavity dispersion on output characteristics and repetition rate tunability was studied.In a range of negative cavity dispersion,the mode-locked fiber laser could output the nearly same spectrum when the repetition rate was tuned,and the output spectrum was nearly Gaussian-type.Based on this result,a simple scheme,spatial optical path structure,and optimized cavity parameters was designed,which promised the large tunable range and stable mode-locking.The mode-locked fiber could stably output 3.23 mW ultrashort laser pulses with 347 fs dechirped pulse duration.Furthermore,the Yb-fiber laser was locked to the Rb atomic clock so that the repetition rate could be stabilized.The Allan deviation is 2× 10-10 when the average time was 1 s.