AlGaAs-On-Insulator Nonlinear Photonics

TL;DR

This paper demonstrates AlGaAs-on-insulator micro-resonators capable of generating broad frequency combs at telecom wavelengths with low power thresholds, highlighting its potential for integrated nonlinear photonics applications.

Contribution

The authors developed a new fabrication process for high-Q AlGaAs-on-insulator micro-resonators, enabling efficient Kerr frequency comb generation at telecom wavelengths.

Findings

Achieved high-quality-factor (Q>100,000) micro-resonators.

Recorded low threshold power of 3 mW for optical parametric oscillation.

Generated a frequency comb spanning 350 nm.

Abstract

The combination of nonlinear and integrated photonics has recently seen a surge with Kerr frequency comb generation in micro-resonators as the most significant achievement. Efficient nonlinear photonic chips have myriad applications including high speed optical signal processing, on-chip multi-wavelength lasers, metrology, molecular spectroscopy, and quantum information science. Aluminium gallium arsenide (AlGaAs) exhibits very high material nonlinearity and low nonlinear loss when operated below half its bandgap energy. However, difficulties in device processing and low device effective nonlinearity made Kerr frequency comb generation elusive. Here, we demonstrate AlGaAs-on-insulator as a nonlinear platform at telecom wavelengths. Using newly developed fabrication processes, we show high-quality-factor (Q>100,000) micro-resonators with integrated bus waveguides in a planar circuit where optical parametric oscillation is achieved with a record low threshold power of 3 mW and a frequency comb spanning 350 nm is obtained. Our demonstration shows the huge potential of the AlGaAs-on-insulator platform in integrated nonlinear photonics.