Abstract:A low-threshold efficient high-repetition-rate eye-safe optical parametric oscillator (OPO) is presented. The OPO is based on an x-cut non-critically phase-matched (NCPM) KTA intra-cavity pumped by an acousto-optically (A-O) Q-switched Nd:YVO4 laser. At 10 kHz, the lowest threshold of 0.75 W and the signal power of 0.6 W are got, corresponding to the single pulse energy of 60 μJ and the peak power of 20 kW. Tuning the frequency, the maximum output power at 1536 nm is 1.03 W at 30 kHz with an optical-to-optical conversion efficiency of 12.26%. The fluctuation of the output power is 2.1% during 2 h operation.