Guided-wave frequency doubling in surface periodically poled lithium niobate: competing effects

TL;DR

This paper investigates second-harmonic generation in surface periodically poled lithium niobate waveguides, revealing the interplay of nonlinear effects and enabling evaluation of nonlinear properties and domain depth.

Contribution

It demonstrates the effects of limited ferroelectric domain depth on nonlinear interactions and provides a method to evaluate quadratic nonlinearity and domain depth.

Findings

Observation of nonlinear resonance shift due to cascading effects

Evaluation of quadratic nonlinearity in near-infrared

Measurement of uninverted domain depth

Abstract

We carried out second-harmonic generation in quasi-phase-matched \alpha-phase lithium niobate channel waveguides realized by proton exchange and surface periodic poling. Owing to a limited ferroelectric domain depth, we could observe the interplay between second-harmonic generation and self-phase modulation due to cascading and cubic effects, resulting in a nonlinear resonance shift. Data reduction allowed us to evaluate both the quadratic nonlinearity in the near infrared as well as the depth of the uninverted domains.