Experimental study of multiple optical parametric oscillator based on MgO:APLN and its evolution analysis of back conversion

Abstract

In this paper, a multiple optical parametric oscillator based on MgO:APLN is reported. The polarization structure of MgO:APLN and output coupler transmittance are optimized, with a high repetition rate of 200 kHz and 1064 nm laser pumping. The 1.57 μm and 3.84 μm cross period parameters light output can be achieved by a single poled crystal for the first time. The maximum average output powers of 2.4 W at 1.57 μm and 1.31 W at 3.84 μm are obtained, corresponding to optical-optical conversion efficiency of 11.54% and 6.25%, respectively. For the phenomenon of energy back conversion appearing in the multiple optical parametric oscillation process, the numerical evolution of multi-wave coupling process through the coupled wave equations is investigated, and the concept of “back conversion in energy transmission area” is induced, and indicates that the existence of back conversion in energy transmission area causes the weak gain parameters of optical parametric oscillator to be enhanced twice. The theoretical analyses are basically in agreement with the experimental results.