The work on the development of a high power linearly polarized pulsed Yb fiber laser and a PPMgLN-based optical parametric oscillator (OPO) pumped by the fiber laser is introduced. The fiber laser was set as a MOPA structure which used an acousto-optic Q-switched Nd∶YVO4 laser as the seed and a Liekki large diameter PM double clad fiber as the gain medium. A near fundamental mode laser emission at 1064 nm was obtained from the fiber laser, which delivers a maximum power output of about 17 W at a repetition rate of 50 kHz, with duration of 60 ns, polarization extinction ratio of greater than 10 dB. Using this fiber laser as the pump source to pump a PPMgLN- based OPO, high parametric conversion was achieved in the OPO. At the signal wavelength of 1518 nm, the maximum parametric output was over 9 W with 2.4 W at 3.5 micron when pumped under 16.2 W. The conversion efficiency of the OPO was 58% with a slope efficiency of 68%. At the wavelength of 1491 nm , the maximum parametric output was over 6.6 W with over 2 W at 3.7 micron when pumped under 14 W.