Fig. 1. Schematic of actively Q-switched YDCF fiber laser with AOM

Fig. 2. Output pulse characteristics of Q-switched fiber laser. (a) Output pulse waveforms at different pump powers with square wave modulation frequency of 10 kHz and duty cycle of 1∶1; (b) measured output pulse waveforms at different duty cycles with square wave modulation frequency of 10 kHz and pump power of 7 W; (c) measured output pulse spectrum with square wave modulation frequency of 10 kHz, pump power of 7 W and duty cycle of 1∶10, in where inset shows spectrum with logarithmic coordinat

Fig. 3. Output pulse characteristics with the square wave modulation frequency of 150 kHz and 155 kHz. (a) Output pulse waveforms with the square wave modulation frequency of 150 kHz, the duty cycle of 1∶53, and the pump power of 7 W; (b) output pulse waveforms with the square wave modulation frequency of 155 kHz, the duty cycle of 1∶64, and the pump power of 7 W; (c) backward spectra measured at the idle pump port of MPC with square wave modulation frequencies of 150 kHz and 155 kHz, respectively; (d)

Fig. 4. Output pulse characteristics with the square wave modulation frequency of 170 kHz, the duty cycle of 1∶50,and the pump power of 7 W by using a FBG with 1-nm bandwidth in the laser. (a) Pulse train; (b) pulse waveform; (c) pulse spectrum

Fig. 5. Relationship among pulse width, output energy, and repetition rate of output Q-switched pulse