Fiber-laser-pumped high-repetition-rate picosecond optical parametric generation and amplification in MgO:PPLN.

Abstract

We report the generation of tunable high-repetition-rate picosecond pulses in the near-infrared at high average power with record conversion efficiency using single-pass optical parametric generation (OPG) and amplification (OPA) in MgO:PPLN, for the first time, to the best of our knowledge. By deploying a mode-locked Yb-fiber laser at 1064 nm providing 21 ps pump pulses at 80 MHz, and a cascade of two 50-mm-long MgO:PPLN crystals, we generate up to 8.3 W of total average output power at a conversion efficiency of 59% over a tunable range of 513 nm, across 1902-2415 nm, with a record threshold as low as 600 mW (7.5 nJ). The two-stage OPG-OPA scheme provides control over fine wavelength tuning and output spectral bandwidths, enabled by the independent control of phase-matching in each crystal. The OPG-OPA output exhibits high spatial beam quality and excellent passive power and central wavelength stability better than 0.9% rms and 0.1% rms, respectively, over 1 hour. The output pulses have a duration of ∼11ps, with a 10 dB bandwidth of ∼350nm at 2107 nm.