报道了一种基于非线性光纤环形镜的工作在耗散孤子共振(DSR)区域的被动锁模掺铒光纤激光器,分别在反常和正常色散区获得了方波脉冲输出。在腔内净色散值约为-0.32ps 2的反常色散区,当泵浦功率为481.2mW时,获得了最大时域宽度为33ns、单脉冲能量约为12.4nJ的方波脉冲。通过在腔内插入一段7m长的色散补偿光纤,使激光器工作在腔内净色散值约为2.85ps 2的正常色散区,在同样的泵浦条件下,获得了最大时域宽度为34.3ns、单脉冲能量约为9.42nJ的方波脉冲。这表明在满足腔内参数平衡的条件下,DSR方波脉冲可同时在反常和正常色散区产生。另外,还研究了泵浦功率对方波脉冲的时域宽度和单脉冲能量的影响,结果表明,随着泵浦功率的增加,方波脉冲的时域宽度和单脉冲能量均呈线性变化。

The passive mode-locked erbium-doped fiber laser based on nonlinear optical loop mirror operating in the dissipative soliton resonance (DSR) region is reported. Square wave pulse output is obtained in the abnormal and normal dispersion regimes respectively. At anomalous dispersion regime, the net cavity dispersion is calculated to be -0.32ps 2. Stable square pluses with maximum temporal pulse duration of 33ns are obtained when the pump power is adjusted to 481.2mW. Correspondingly, the single pulse energy is 12.4nJ. Subsequently, a 7m long dispersion compensating fiber is employed to compensate the cavity dispersion to make the laser system work at the normal dispersion regime and the net cavity dispersion is 2.85ps 2. Under the same pump power, the maximum temporal duration of the square pulses is 34.3ns and the single pulse energy is 9.42nJ. It is shown that DSR square pulses can be generated at both anomalous and normal dispersion regimes under the conditions of balanced cavity parameters. Additionally, the influence of the pump power on the time domain width and single pulse energy of square wave pulse is also studied. The results show that the time domain width and single pulse energy of square wave pulse change linearly with the increase of pump power.