Abstract
In the thesis, we studied the chirped pulse amplification (CPA) system based on a dual-stage Yb-doped polarization-maintaining (PM) fibers seeded with a picosecond-scale all-normal dispersion (ANDi) fiber laser with pulse duration of 15 ps and average output power of 50 mW. The dual-stage amplifier was composed of 7-m-long 10-μm Yb-doped PM fiber and 5-m-long 30-μm Yb-doped PM fiber as a pre-amplifier and a main amplifier, respectively. In the experiment, due to strong nonlinearities induced by PM fibers and third order dispersion (TOD) of the fiber stretcher, we could not obtain sub-picosecond pulses in CPA system. But the power efficiency was raised up to about 50% for the characteristic of PM fibers in maintaining polarization of pulses so that the power would not loss due to the selection of polarization in grating compressor. Under the condition of the best compensation in SOD and TOD, the highest peak power of the compressed pulse was ~90 kW with pulse duration of 1.7 ps in FWHM and 1.94 ps in EA definition and the pulse energy was 174 nJ with 65% pulse energy concentration which was improved up to 35% comparing to normal-fiber-based CPA system.