提出一种在非高重复频率下获得窄脉宽脉冲输出的呼吸孤子掺铒光纤激光器设计方案。通过缩短腔内具有大色散系数的正负色散光纤的长度来保证腔内脉冲有较大的呼吸比,通过引入零色散光纤来降低激光器的重复频率。采用波分复用器及隔离器集于一体的光纤混合器,并以前向抽运方式来降低腔内脉冲能量的损耗,并且通过优化腔内负色散光纤的分布来确定输出端的位置。基于此,构建出重复频率为100 MHz的呼吸孤子掺铒光纤激光器,其输出光谱宽度为112 nm,直接输出脉冲宽度为68 fs,色散补偿后的输出脉冲宽度为39 fs,当抽运功率为900 mW时输出脉冲的平均功率为94.5 mW。

This study proposes a structural design for a breath soliton erbium (Er)-doped fiber laser under a relatively low (100 MHz) repetition rate to obtain a pulse output having narrow pulse width. An output pulse with a large breathing ratio can be ensured by shortening the lengths of the positive and negative dispersion fibers with a large dispersion coefficient in the cavity. And, a fiber with zero dispersion is introduced to reduce the repetition rate of the laser. The energy loss of the pulse in the cavity is reduced using a fiber optic mixer, which integrates the wavelength division multiplexer and the isolator with the forward pumping method. The distribution of the negative dispersion fiber in the cavity is optimized and designed to determine the output position of the laser. Based on this, a breath soliton Er-doped fiber laser having a repetition rate of 100 MHz is constructed; the laser's output spectrum and direct output pulse width are 112 nm and 68 fs, respectively. After dispersion compensation, the laser's output pulse width is 39 fs, and its average power of output pulse is 94.5 mW at a pump power of 900 mW.