High power nanosecond pulsed fiber laser amplifiers

This project is to develop a high power nanosecond pulsed fiber laser amplifier using large mode area fibers doped with Ytterbium. It first focuses on building an all-fiber master oscillator power amplifier (MOPA) system that is capable of performing at high peak power and pulse energy with high beam quality. The performance of the MOPA then is improved in term of the usability of the output pulse with active adaptive pulse shaping. A gain-switched setup is also investigated as a 1060nm picosecond pulse source for the MOPA. Injection and self seeding are comparatively studied using the EOM-FROG technique. It is concluded that the inexpensive and simple self seeding gives similar performance compared to the expensive injection seeding using a distributed feed back laser. Pulses of 1GHz in repetition rate and 70ps in duration are produced directly from the diode. A linearly chirped Bragg fiber gratings is used to compress the pulse to below 20ps reducing the time bandwidth product from 3 to 0.7