Patent ID: 8009705

Claim:
A method for generating a pulsed optical signal, comprising: generating one or more chirped input pulses with a laser seed source by pulsing a drive current applied to a semiconductor diode laser with square current pulses characterized by a repetition rate between about 50 kilohertz and about 100 Megahertz and a duty cycle of less than about 5%, wherein the input pulses are characterized by a pulse duration τ and a frequency chirp wherein τ is greater than about 2 nanoseconds; optically coupling the one or more chirped input pulses from the laser seed source into a photonic crystal fiber optical amplifier; and amplifying the input pulses with the photonic crystal fiber optical amplifier to produce one or more amplified pulses characterized by a peak power P greater than about 1 kilowatt, wherein the frequency chirp and the photonic crystal fiber are selected such that a threshold for stimulated Brillouin scattering (SBS) in the photonic crystal fiber is greater than the peak power P, wherein pulsing the drive current increases a chirp rate of the frequency chirp by an amount sufficient to raise the threshold for SBS of the optical amplifier above a peak power for the optical amplifier.