US Patent 8009705 Fiber MOPA system without stimulated brillouin scattering

Methods and systems for increasing the threshold for stimulated Brillouin scattering are described. A seed source may generate one or more chirped seed pulses characterized by a pulse duration τ, and a frequency chirp. The pulse duration τ may be greater than about 2 nanoseconds. A photonic crystal amplifier amplifies the seed pulses to produce one or more amplified pulses characterized by a peak power P greater than about 1 kilowatt. The pulse duration τ, frequency chirp, and the photonic crystal fiber may be selected such that a threshold for stimulated Brillouin scattering (SBS) in the photonic crystal fiber is greater than the peak power P.