title: Coherent polarization beam combination of four mode-locked fiber MOPAs in picosecond regime.
abstract: In this manuscript, we report on coherent polarization beam combination (CPBC) of a four-channel pulsed amplifier array in the picosecond regime by using single frequency dithering technique. By employing a photo-detector with low-pass bandwidth (8.5 MHz at 10 dB gain) to filter the intensity fluctuation and obtain phase errors for feedback, a combined laser pulse with~480 ps pulse width at~60 MHz repetition rate is obtained with an average power of 88 W. By adjusting the optical path differences (OPDs) and controlling the pump power to ensure the synchronizations and alleviate the influence of nonlinear phases among each channel, more than 90% combining efficiency is achieved with excellent beam quality (M(2)~1.1). Finally, the efficiency loss of the system along with the power scaling process is discussed.
authors.forename: Pengfei
authors.initials: P
authors.lastname: Ma
authors.forename: Rumao
authors.initials: R
authors.lastname: Tao
authors.forename: Xiaolin
authors.initials: X
authors.lastname: Wang
authors.forename: Yanxing
authors.initials: Y
authors.lastname: Ma
authors.forename: Rongtao
authors.initials: R
authors.lastname: Su
authors.forename: Pu
authors.initials: P
authors.lastname: Zhou