Injection-Locked Mode-Locked Laser With Long-Term Stabilization and High Power-per-Combline

A novel method is presented to provide long-term stabilization of an injection-locked harmonically mode-locked laser to a narrow linewidth continuous-wave (CW) source for the first time. The method, based on the Pound-Drever-Hall method of laser frequency stabilization, exploits the phase shift across a laser cavity mode resonance to detect the offset between the CW frequency and the combline frequency desired for injection-locking. Long-term suppression of the radio-frequency supermode noise spurs is shown as well as 36-dB suppression of optical supermodes. Significant reductions in phase and amplitude noise are also shown due to injection. Postamplification noise results are presented, showing an increase in optical power per combline with no degradation in pulse-to-pulse energy fluctuation or timing jitter.