# Optomechanical Gigahertz Oscillator made of a Two Photon Absorption free piezoelectric III/V semiconductor

## TL;DR

This paper demonstrates a 3 GHz optomechanical oscillator using a bichromatic crystal made of TPA-free InGaP, achieving low power operation, narrow linewidth, and high stability suitable for telecommunication and timing applications.

## Contribution

It introduces a novel bichromatic optomechanical crystal design made of TPA-free InGaP, enabling self-sustained 3 GHz oscillations with low power and high stability in ambient conditions.

## Key findings

- Achieved 3 GHz self-sustained oscillations at low optical power (40 μW)
- Narrowed linewidth to 100 Hz, indicating high frequency stability
- Demonstrated operation in ambient atmospheric conditions

## Abstract

Oscillators in the GHz frequency range are key building blocks for telecommunication, timing and positioning applications. Operating directly in the GHz and compactness while keeping high frequency stability, is still an up-to-date challenge. Recently, optomechanical crystals, compact by nature, have demonstrated GHz frequency modes, thus gathering prerequisite features for using them as oscillators. Here we report on the demonstration, in ambient atmospheric conditions, of an optomechanical oscillator designed with an original concept based on bichromatic one-dimensional optomechanical crystal. Self sustained oscillations directly at 3 GHz are routinely achieved with a low optical power threshold of 40 $\mu W$ and short-term linewidth narrowed down to 100 Hz in agreement with phase noise measurements (-113 dBc/Hz at 1 MHz from the carrier) for free running optomechanical oscillators. This oscillator is made of InGaP, low loss and TPA-free piezoelectric material which makes it valuable for optomechanics.