Optomechanical gigahertz oscillator made of a two photon absorption free piezoelectric III/V semiconductor

Abstract

Oscillators in the gigahertz frequency range are key building blocks for telecommunication and positioning applications. Operating directly in the gigahertz while keeping high frequency stability and compactness is still an up-to-date challenge. Optomechanical crystals have demonstrated gigahertz frequency modes, thus gathering prerequisite features for using them as oscillators. Here, we report on the demonstration, in ambient atmospheric conditions, of an optomechanical crystal based on the concept of bichromatic lattice. It is made of InGaP, a low loss and TPA-free piezoelectric material, which makes it valuable for optomechanics. Self-sustained oscillations directly at 3 GHz are routinely achieved with a low optical power threshold of 40 μW and a short-term linewidth narrowed down to 100 Hz in agreement with phase noise measurements (−110 dBc/Hz at 1 MHz from the carrier) for free running optomechanical oscillators.