MEGAHERTZ-REPETITION-RATE ND-GLASS FIBER LASER

Stable trains of 100-200-ns-long pulses are obtained at 0.46-1.06-MHz repetition rates in a Nd:glass fiber laser by driving large-amplitude relaxation oscillations at or below their resonance. Numerical simulat ions agree qualitatively with temporal profiles of the output power. W e show that the maximum pulse-repetition rate of a relaxation-oscillat ion laser increases as the square root of pump power at low P and that its theoretical upper limit is close to the pulse rate of a mode-lock ed laser. (C) 1996 Optical Society of America