Compact V-Type Cavity for Harmonically Pumped 1-GHz Femtosecond Optical Parametric Oscillator

In this letter, we propose and demonstrate a practically compact 1-GHz repetition-rate femtosecond optical parametric oscillator (OPO) based on MgO:PPLN crystal, which is harmonically pumped by a 53 MHz Yb-doped fiber laser. The multiplication of the repetition rate is derived by placing the nonlinear crystal in a miniaturized V-type cavity with 13.9 cm length. The near-infrared signal output pulses are tunable from 1350 nm to 1650 nm. The signal pulse duration across the complete tuning range is measured to be around 125 fs. Thanks to the high repetition rate, broadband tenability, and simplicity of the optical setup, this type of OPO holds promise for many applications.