Multi-gigahertz picosecond optical parametric oscillator pumped by 80-MHz Yb-fiber laser.

We report a multi-gigahertz (GHz) repetition-rate picosecond optical parametric oscillator (OPO) based on MgO:PPLN, synchronously pumped by a Yb-fiber laser operating at 80 MHz, where the multiplication of repetition frequency is achieved using fractional increment in the OPO cavity length. Using this simple technique, we achieve OPO operation up to the 88th harmonic of the pump laser frequency, corresponding to a repetition rate as high as 7 GHz. Deploying a 5% output coupler, we are able to extract up to 960 mW of average signal power at the fundamental with 600 mW at the 88th harmonic (7 GHz), using a pump power of 5.6 W. The measured relative standard deviations of the fundamental and fifth harmonic signal power are recorded to be 1.6% and 3.5%, respectively, while the fundamental signal pulse duration is measured to be 18.4 ps.