High-power high repetition rate picosecond optical parametric oscillator pumped by frequency doubled all-fiber Yb-doped MOPA

We demonstrate a lithium triborate (LBO) optical parametric oscillator (OPO), which is synchronously pumped with a pulse-compressed and frequency-doubled master-oscillator power-amplifier (MOPA) system consisting of a gain-switched laser diode and a series of Ytterbium-doped fiber amplifiers. The 20ps pulses from the MOPA were compressed in a transmission grating compressor down to 4.4ps with a throughput efficiency of similar to 70% and subsequently frequency-doubled with an efficiency of similar to 60% in a 20mm long LBO to a maximum of similar to 25W. With a typical pump power of 17W for the OPO, we obtained a maximum combined signal and idler output power of 2.5W (at 877nm) and 1.7W (at 1.3 mu m). Individually, a maximum signal power of up to 3.7W at 740 nm was obtained with a signal pulse duration of similar to 3.2ps. The OPO was widely tunable from 651nm-1040nm (signal) and from 1081nm-2851nm (idler). To the best of our knowledge, this is the highest output power from a green-pumped LBO OPO. The fiber-based pump source can potentially be operated between 100MHz and 1GHz, which in combination with the few-picosecond pulses and the near-IR tunability of the OPO is a very attractive source for nonlinear microscopy.