Backward wave optical parametric oscillation in a waveguide

A backward wave optical parametric oscillator (BWOPO) waveguide in periodically poled Rb-doped KTP is presented. The waveguide exhibits low loss (0.16 dB/cm) and has an oscillation threshold, almost 20 times lower than the corresponding bulk device. The backward wave has a narrow linewidth of 21 GHz at 1514.6 nm while the forward wave at 1688.7 nm has a spectrum replicating the pump. The unique spectral features of the BWOPO will unlock novel opportunities in low-power nonlinear integrated optics. A conversion efficiency of 8.4 obtained limited by the emergence of backward stimulated polariton scattering.