Self-excited oscillation and synchronization of an on-fiber optomechanical cavity

A lensed fiber Bragg grating-based membrane-in-the-middle optomechanical cavity

Optomechanical systems benefit from the coupling between an optical field and mechanical vibrations. Fiber-based devices are well suited to easily exploit this interaction. We report an alternative approach of a silicon nitride membrane-in-the-middle of a high quality factor ([Formula: see text]-[Formula: see text]) Fabry-Perot, formed by a grating inscribed within a fiber core as an input mirror in front of a dielectric back mirror. The Pound-Drever-Hall technique used to stabilize the laser frequency on the optical resonance frequency allows us to reduce the low frequency noise down to [Formula: see text]. We present a detailed methodology for the characterization of the optical and optomechanical properties of this stabilized system, using various membrane geometries, with corresponding resonance frequencies in the range of several hundred of [Formula: see text]. The excellent long-term stability is illustrated by continuous measurements of the thermomechanical noise spectrum over several days, with the laser source maintained at optical resonance. This major result makes this system an ideal candidate for optomechanical sensing.

Two-Membrane Cavity Optomechanics: Linear and Non-Linear Dynamics

In this paper, we review the linear and non-linear dynamics of an optomechanical system made of a two-membrane etalon in a high-finesse Fabry–Pérot cavity. This two-membrane setup has the capacity to modify on demand the single-photon optomechanical coupling, and in the linearized interaction regime to cool simultaneously two mechanical oscillators. It is a promising platform for realizing cavity optomechanics with multiple resonators. In the non-linear regime, an analytical approach based on slowly varying amplitude equations allows us to derive a consistent and full characterization of the non-linear displacement detection, enabling a truthful detection of membrane displacements much above the usual linear sensing limited by the cavity linewidth. Such a high quality system also shows a pre-synchronization regime.