Third-Harmonic Generation at 1594 nm in a KTP Ridge Optical Waveguide

We achieved birefringence phase-matched Third-Harmonic Generation at 1594 nm in a KTiOPO4 single crystal ridge optical waveguide. The energy conversion efficiency reached 3.4% for a pump energy as low as 2 µJ over a pulse duration of 15 ps. Strong agreements between theory and experiments for phase-matching and conversion efficiency were obtained.