This paper presents a theoretical study of optomechanical systems in which the mechanical resonator modulates both the resonant frequency (dispersive coupling) and the decay rates (dissipative coupling) of the optical cavity. The generic dispersive framework is extended to a more general case in which the dissipative coupling is split between its external and intrinsic contribution. We report a complete analysis of the influence of both external and intrinsic optical losses on each of the three coupling mechanisms, highlighting the interest of each optical loss regime. A presentation of the basic model to experimentally identify the three couplings and their relative influence on the optical response is proposed. We also extend the basic tools by analyzing the mechanical dynamics and demonstrating the general expression of the optical spring effect and of optomechanical damping. A comparison between our theoretical model and experimental measurements in photonic crystal systems from the literature yields good agreement.

No abstract

No abstract

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 ($$10^6$$ 10 6 –$$10^7$$ 10 7 ) 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 $${4}\,{{\mathrm{kHz}}/\sqrt{\mathrm{Hz}}}$$ 4 kHz / Hz . 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 $${\mathrm{kHz}}$$ kHz . 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.