Heterogeneously integrated gallium phosphide optomechanical oscillator on Soi waveguides

Abstract

We present a one dimensional photonic crystal, made of Gallium-Phosphide, as an optomechanical oscillator with low phase noise. The heterogenous integration on Silicon-on-Insulator circuitry allows the evanescently coupling of light at telecom wavelengths from the silicon waveguides into the photonic wire crystal. Thanks to the strong interaction between the optical field and mechanical field, the mechanical oscillation at 3.35 GHz is directly imprinted on the optical carrier. An external opto-electronic feedback loop with time-delay is constructed to further stabilize the oscillation. We achieved a phase noise of -111dBc/Hz at 100 kHz offset frequency with sub-Hz linewidth of 0.67 Hz.