Published the June 15, 2023

Sub-Hz closed loop electro-optomechanical oscillator with Gallium phosphide photonic crystal integrated on SoI circuitry

We report on a new approach of a low phase noise electro-optomechanical oscillator directly working in the GHz frequency range. The developed nano-scale oscillator is a one-dimensional photonic crystal made of GaP, heterogeneously integrated on silicon-on-insulator circuitry. Based on the strong interaction between the optical mode at telecommunication wavelength and the mechanical mode in the GHz, ultra-pure mechanical oscillations are enabled and directly imprinted on an optical carrier. Further stabilization is achieved with delayed opto-electronic feedback loop using integrated electro-mechanical self-injection. We achieve a short-term stability of 0.7 Hz linewidth and long-term with an Allan deviation below 10-7 Hz/Hz at 10 s averaging time, which represents an important step towards fully integrated optomechanical oscillators. Integrability, and the low phase noise of this oscillator address some of the most important needs of optoelectronic oscillators and pave the way towards on-chip integrated microwave oscillators for microwave applications such as RADARs.

Sub-Hz Closed-Loop Electro-Optomechanical Oscillator with Gallium Phosphide Photonic Crystal Integrated on SoI Circuitry
Róbert Horváth1, Giuseppe Modica1, Inès Ghorbel2, Grégoire Beaudoin1, Konstantinos Pantzas1, Isabelle Sagnes1, Aude Martin2, Alfredo De Rossi2, Sylvain Combrié2, and Rémy Braive1
ACS Photonics 2023

1 Centre de Nanosciences e de Nanotechnologies, CNRS, Université Paris Saclay, Palaiseau, France
2 Thales Research and Technology, Campus Polytechnique, Palaiseau, France

Keywords : optomechanics, 1D photonic crystal, oscillators, heterogenous integration, phase noise, optoelectronic feedback loop

Caption : a scanning electron microscope (SEM) image of single optomechanical crystal (coloured  in blue) on top of a SOI waveguide (red) with the electrodes (yellow) framing the device.

Contact : Rémy Braive