Interferometeric output coupling of a continuous-wave optical parametric oscillator

Abstract

We demonstrate the use of an antiresonant ring (ARR) interferometer for optimum output coupling in a continuous-wave singly-resonant optical parametric oscillator (SRO). The cw SRO, based on a 50-mm-long MgO:PPLN crystal in a standing-wave cavity, is pumped by cw Ytterbium fiber laser at 1064 nm. The ARR interferometer is integrated into one arm of the SRO cavity. By fine adjustment of the ARR transmission, a continuously variable signal output coupling from 0.8% to 7.3% has been achieved, resulting in an optimum output coupling of ~4.6% for 23.2 W of input pump power. At this output coupling, the SRO provides 2.28 W of signal, together with 2.95 W of idler, for 23.2 W of pump power. We also show that the deployment of the ARR does not lead to any degradation in the output beam quality from the cw SRO. The technique provides a proof-of-principle demonstration to determine the absolute output coupling in cw SRO for which output power and extraction efficiency can be maximized.