A multi-wavelength switchable random fibre laser based on a double Sagnac-loop filter is proposed. The threshold of laser is 27 mW and the slope efficiency of the total power output to pump power is about 0.04%. In the experiment, stable and switchable laser outputs of single-, dual-, tri- and quad-wavelength channels are obtained by adjusting the polarization controller at room temperature. The wavelength positions are tuneable within the range of 1556–1564 nm and intervals are switchable between 2.5, 5 and 7.5 nm. Under 300 mW pump power, average power intensity of −24dBm is achieved. Furthermore, the output of fibre laser is relatively stable with less than 0.2 nm wavelength drift and less than 1.5 dBm power fluctuation within one hour. The proposed random fibre laser has promising application prospects for distributed sensing systems and biomedical imaging.

提出了一种基于双萨格纳克环路滤波器的多波长可切换随机光纤激光器。激光的阈值为27 mW，总输出功率对泵浦功率的斜率效率约为0.04%。在实验中，通过在室温下调节偏振控制器，获得了稳定且可切换的单、双、三、四波长通道的激光输出。波长位置可在 1556–1564 nm 范围内调谐，间隔可在 2.5、5 和 7.5 nm 之间切换。在 300 mW 泵浦功率下，实现了 -24dBm 的平均功率强度。此外，光纤激光器的输出相对稳定，一小时内波长漂移小于0.2nm，功率波动小于1.5dBm。