Second Harmonic Generation in a Phase-Matched Sub-Micron SiO2-LiNbO3-Air Slab Waveguide

All-optical wavelength conversion is crucial to optical communication and optical computing, since it is central to designing all-optical wavelength division multiplexers [1] and all-optical logic gates [2]. In particular, these applications rely on a structure capable of second harmonic generation (SHG). By realizing this nonlinear phenomenon in a waveguiding structure, SHG can be achieved on a compact platform compatible with photonic integrated circuits. A slab waveguide provides the most benefits, since its planar-nature is ideal for on-chip applications and because the waveguide core (i.e. nonlinear material) has a large area allowing for high pumping energies. Here, we measure SHG in a SiO
₂
-LiNbO
₃
-air slab waveguide having a core thickness of 760 nm. The measurements are in agreement with the performed phase-matching and modal overlap analyses.