Patent ID: 8730570
Filing Date: 2014-05-20
Classification: H01S

Abstract:
1. A method for amplifying laser pulses, comprising: modifying a train of input laser pulses at an input pulse repetition rate to stretch a pulse duration of each input laser pulse to produce a train of stretched laser pulses; directing the train of stretched laser pulses into an optical power amplifier to amplify the stretched laser pulses; guiding the stretched laser pulses that are amplified by the optical power amplifier through an input optical path; coupling the stretched laser pulses that are amplified by the optical power amplifier from the input optical path into a chirped fiber Bragg grating configured as a pulse compressor, to obtain reflected optical pulses from the chirped fiber Bragg grating with compressed pulse durations; directing the reflected optical pulses from the chirped fiber Bragg grating with compressed pulse durations along an output optical path in free space, without going through fiber, to produce amplified output laser pulses with compressed pulse durations; adjusting dispersion of the stretched laser pulses with respect to dispersion of the chirped fiber Bragg grating to optimize compressing of the reflected optical pulses in the output optical path of the chirped fiber Bragg grating; controlling the stretched laser pulses output by the optical power amplifier to be in a first linear polarization; directing the stretched laser pulses from the optical power amplifier into a polarizing beam splitter which directs the stretched laser pulses from the optical power amplifier towards the chirped fiber Bragg grating; rotating polarization of light from the polarizing beam splitter by 45 degrees before directing the light to the chirped fiber Bragg grating; rotating polarization of the reflected optical pulses from the chirped fiber Bragg grating with compressed pulse durations by an additional 45 degrees before directing the reflected optical pulses from the chirped fiber Bragg grating to the polarizing beam splitter; and using the polarizing beam splitter to separate the stretched laser pulses from the optical power amplifier into the polarizing beam splitter and the reflected optical pulses with compressed pulse durations from the chirped fiber Bragg grating and to direct the reflected optical pulses with compressed pulse durations from the chirped fiber Bragg grating along the output optical path in free space, wherein: the input optical path includes a delivery fiber line, and the method comprises: