报道了一种基于非线性光纤环形镜(NOLM)、工作在耗散孤子共振(DSR)区的长腔被动锁模掺镱光纤激光器,该激光器谐振腔的总长度约为1502 m,可以输出重复频率为133.18 kHz的高能量方波脉冲,且输出脉冲的宽度和单脉冲能量均随泵浦功率的增大而呈线性增大。当泵浦功率增大到414.47 mW时,输出的方波脉冲具有最大宽度(761.6 ns),同时单脉冲能量达到了最大值(60.2 nJ)。通过改变NOLM中单模光纤的长度,进一步研究了谐振腔长度对输出方波脉冲特性的影响,结果表明:谐振腔越长,所得DSR方波脉冲越宽,脉冲峰值功率越低。

This paper reports on a passively mode-locked ytterbium-doped fiber laser with a 1502-m total cavity length operating in the dissipative soliton resonance (DSR) region using the nonlinear optical loop mirror (NOLM) technique. High-energy square pulses with an ultra-low repetition rate of 133.18 kHz are observed. Both the duration and single pulse energy of the output DSR pulse increase linearly with increasing pump power. The maximum output pulse duration reaches 761.6 ns at a pump power of 414.47 mW, while the single pulse energy at the same power level reaches 60.2 nJ. In addition, the influence of cavity length on the pulse duration and single pulse energy is investigated by changing the length of the single mode fiber in the NOLM. The results indicate that the longer the cavity length is, the larger the pulse duration is, and the lower the peak power is.