Single-Mode Propagation and Highly Efficient Second Harmonic Generation in Periodically Poled MgO-Doped LiNbO₃ on Insulator Rib Waveguide

Theoretical studies on mode propagation and second harmonic generation in periodically poled MgO-doped LiNbO₃ on an insulator (PPLNOI) rib waveguide are presented. With a special design, the waveguide can simultaneously support the single-mode propagation of both a pump wave (1550 nm) and a second harmonic wave (775 nm). As a result of the strong confinement and intensive nonlinear effect in the PPLNOI rib waveguide, the calculated results indicate that a second-harmonic generation conversion efficiency of 400%W^?1?cm^?2 can be achieved at a wavelength of 1550 nm, almost 2.6 times higher than the widely applied reverse proton-exchanged waveguide (150%W^?1?cm^?2).