PPMgLN-Based High-Power Optical Parametric Oscillator Pumped by Yb3+-Doped Fiber Amplifier Incorporates Active Pulse Shaping

We report a periodically poled magnesium-oxide-doped lithium niobate (PPMgLN) based optical parametric oscillator (OPO) pumped by a diode-seeded, linearly polarized, high-power, pulsed, ytterbium fiber master oscillator power amplifier (MOPA). Using adaptive pulse shaping of the seed laser (using an external modulator), we demonstrate a reduction in the impact of dynamic gain saturation and optical Kerr/Raman nonlinearities within the fiber MOPA, obtaining shaped signal and idler pulses at the OPO output and reduced spectral bandwidths. A maximum average output power of 26.5 W was obtained from the MOPA at 1062 run. An output power as high as 11 W from the OPO at an overall slope efficiency of 67% was achieved, with 2.7 W of output power obtained at a wavelength of 3.5 mu m. Our experiments were pump-power-limited and considerable scope remains for further power scaling of such OPOs using this approach.