Abstract

The idler conversion efficiency of optical parametric oscillators (OPOs) can be increased by adding a second nonlinear crystal in the cavity. This crystal is pumped by the signal and acts as an optical parametric amplifier (OPA) for the idler. This OPO–OPA (or OPO-DFM) scheme was firstly proposed by Koch et al in 1995 [1]. Improvement of the idler quantum efficiency was then experimentally demonstrated in picosecond and nanosecond regimes [2,3]. However, the use of two separate nonlinear crystals within the OPO cavity induces additional interface loss, increases the oscillation build-up time, and leads to a more complex OPO architecture, which prevent to fully benefit of the OPO–OPA scheme [4,5].

© 2011 Optical Society of America