Second harmonic generation in monolithic GaAs shallow waveguides

Photonic circuits based on quadratically nonlinear semiconductors with a direct energy bandgap have not known the broad development of silicon-on-insulator technology. Their integration is enabled by high-index-contrast waveguides with a III-V core bonded on a low-index insulator, which are much shallower than their deeply etched low-contrast monolithic counterparts but have not proven to be an easy industrial up-scaling. Here we propose a compromise between these two options, by using a mature laser-diode material like aluminum gallium arsenide to demonstrate low-contrast monolithic waveguides that are performant in terms of frequency conversion.