Abstract
We have constructed the front-end system using a broadband high-gain OPCPA for chirped pulse amplifica-tion. This system can deliver the output energy of 65 mJ with 6-nm spectral width at a 1.053-lim central wavelength. The stability of output energy was substantially improved compared with the Ti: Al2O3 regenera-tive amplifier. These output parameters are appropriate as a seed of PW-class Nd: glass laser system.