Output optimization of a high-repetition-rate diode-pumped Q-switched intracavity optical parametric oscillator at 1.57 μm

The output optimization of a high-repetition-rate diode-pumped Q-switched intracavity optical parametric oscillator at 1573 nm with a type-II non-critically phase-matched x-cut KTP is experimentally and theoretically studied. The optimum output reflectivity is found to be 85%-90% for the maximum average power. The average conversion efficiency from diode-laser input power to OPO signal output power is up to 15% at a pulse repetition of 80 kHz. However, the optimum output reflectivity for the maximum peak power is found to be 60%-70%; the overall peak power amounts to 3-4 kW at a pulse repetition of 80 kHz.