Continuous-Wave Second-Harmonic Generation in Orientation-Patterned GaP Waveguides at Telecom Wavelengths

TL;DR

This paper presents a novel process for fabricating high-quality orientation-patterned GaP waveguides that enable efficient second-harmonic generation at telecom wavelengths, demonstrating high conversion efficiency and good uniformity.

Contribution

The authors develop a new method to produce nearly perfectly parallel domain boundaries in OP-GaP on GaAs, enabling efficient SHG in integrated waveguides at telecom wavelengths.

Findings

Achieved 200%/W/cm^2 conversion efficiency in OP-GaP waveguides.

Demonstrated a 2.67 nm bandwidth for SHG.

Confirmed uniform poling period through wavelength dependence matching theory.

Abstract

A new process to produce Orientation-Patterned Gallium Phosphide (OP-GaP) on GaAs with almost perfectly parallel domain boundaries is presented. Taking advantage of the chemical selectivity between phosphides and arsenides, OP-GaP is processed into suspended shallow-ridge waveguides. Efficient Second-Harmonic Generation from Telecom wavelengths is achieved in both Type-I and Type-II polarisation configurations. The highest observed conversion efficiency is \SI{200}{\percent\per\watt\per\centi\meter\squared}, with a bandwidth of \SI{2.67}{\nano\meter} in a \SI{1}{\milli\meter}-long waveguide. The variation of the conversion efficiency with wavelength closely follows a squared cardinal sine function, in excellent agreement with theory, confirming the good uniformity of the poling period over the entire length of the waveguide.