Patent ID: 7477667

Claim:
A fiber Chirped Pulse Amplification (CPA) laser system, comprising: a fiber mode-locking oscillator configured to generate a train of first laser pulses having a first pulse width at an input repetition rate; a pulse stretcher configured to receive the train of first laser pulses to produce a train of stretched laser pulses having a second pulse width at least 1000 times of the first pulse width; an acoustic-optic device configured to produce a modulated acoustic grating at a picking repetition rate lower than 1/100 th of the input repetition rate, wherein the modulated acoustic grating is configured to select one of the stretched laser pulses in the train of stretched laser pulses to produce a selected stretched laser pulse, wherein the selected stretched laser pulse has a pulse energy below 10 μJ; a first high-energy amplifier constructed in a large mode area (LMA) fiber, wherein the first high-energy amplifier is configured to produce a first amplified pulse in response to the selected stretched laser pulse; a second high-energy amplifier constructed in a Yb doped photonic crystal fiber (PCF) fiber, wherein the second high-energy amplifier is configured to produce a second amplified pulse in response to the first amplified pulse; and a compressor configured to compress the second amplified pulse to produce an output laser pulse shorter than the second amplified pulse, wherein the output laser pulse has a pulse energy above 1 mJ.