在激光器输出平均功率一定的情况下，峰值功率主要取决于调制频率和脉冲宽度。这使得脉冲宽度的调节具有一定的实际应用价值。对调Q掺铥双包层光纤激光器进行研究，首先确定了激光器的最佳输出透过率，在65%最佳透过率时，得到2 μm激光的输出功率3.9 W，斜率效率为31%。外接一个信号发生器，信号门宽从12 μs变化到18 μs，并测量了调制频率分别在30 kHz、40 kHz和50 kHz时输出脉冲宽度的变化情况，得到了555.6 W的最高峰值功率，实现了脉冲宽度从163.4 ns到207.9 ns的变化。实验情况证实了用外接信号发生器能有效控制激光器的输出脉冲宽度。

The peak power is determined by the modulation frequency and pulse width with the average output power of laser settled, thus the tunability of pulse width has its value in practice.The thulium-doped Q-switched double-clad fiber laser was investigated. With optimum transmissivity of 65% the output power of 2 μm laser was 3.9 W and the corresponding slope efficiency was 31%. The signal gate width was adjusted from 12 μs to 18 μs with the external signal generator. Pulse width was measured at modulation frequency of 30 kHz, 40 kHz and 50 kHz, and maximum peak power of 555.6 W was attained. The pulse width varied from 163.4 ns to 207.9 ns. The experiment result shows pulse width of laser can be effectively controlled by using external signal generator.