Fig. 1. Optical path diagram of nanosecond pulse train laser seed source system with physical image of SOA module shown in inset

Fig. 2. 8.8 ns single pulse waveform output by SOA

Fig. 3. SOA absorption and output power versus input power. (a) SOA absorption curve and absorption ratio without electrical signal excitation; (b) output power of SOA versus input power under working voltage of 1.4 V

Fig. 4. SOA output spectra, SNR, signal optical amplification gain, and extinction ratio versus input power. (a) SOA output spectra; (b) SNR and amplified signal optical power; (c) signal optical amplification gain and extinction ratio

Fig. 5. Output power of SOA versus input optical power when trigger signal amplitude is 1.0‒1.8 V at working frequency of 100 kHz

Fig. 6. Laser waveforms output by seed source system. (a) Repetition rate of 10 kHz; (b) repetition rate of 100 kHz; (c) pulse train waveform

Fig. 7. SOA output spectrum

Fig. 8. SOA output beam quality and spot shape

Fig. 9. Single pulse waveforms with variable pulse width output by seed source system. (a) Trigger signal pulse width of 20 ns; (b) trigger signal pulse width of 40 ns ; (c) trigger signal pulse width of 60 ns ; (d) trigger signal pulse width of 80 ns ; (e) trigger signal pulse width of 100 ns; (f) single pulse energy versus trigger signal pulse width

Fig. 10. Average output power of seed source system versus SOA operating voltage at operating frequency of 10‒100 kHz

Fig. 11. Stability of single pulse energy output by seed source system

Fig. 12. YDFA output spectrum

Fig. 13. YDFA output beam quality and spot shape