Second-harmonic generation in periodically-poled thin film lithium niobate wafer-bonded on silicon

TL;DR

This paper demonstrates efficient second-harmonic generation in thin film lithium niobate waveguides bonded on silicon, highlighting their potential for integrated nonlinear and quantum photonics applications.

Contribution

It introduces a novel platform of periodically-poled thin film lithium niobate on silicon with rib-loaded waveguides for efficient second-order nonlinear effects.

Findings

8% nonlinear conversion efficiency achieved

Waveguides are compact (~2 μm^2 cross-section)

Platform is compatible with silicon photonics

Abstract

Second-order optical nonlinear effects (second-harmonic and sum-frequency generation) are demonstrated in the telecommunication band by periodic poling of thin films of lithium niobate wafer-bonded on silicon substrates and rib-loaded with silicon nitride channels to attain ridge waveguide with cross-sections of ~ 2 {\mu}m2. The compactness of the waveguides results in efficient second-order nonlinear devices. A nonlinear conversion of 8% is obtained with a pulsed input in 4 mm long waveguides. The choice of silicon substrate makes the platform potentially compatible with silicon photonics, and therefore may pave the path towards on-chip nonlinear and quantum-optic applications.