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arXiv · 1611.01567

Thermal Brillouin noise observed in silicon optomechanical waveguide

Raphaël Van Laer·Christopher J. Sarabalis·Roel Baets·Dries Van Thourhout·Amir H. Safavi-Naeini
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Abstract

Stimulated Brillouin scattering was recently observed in nanoscale silicon waveguides. Surprisingly, thermally-driven photon-phonon conversion in these structures had not yet been reported. Here, we inject an optical probe in a suspended silicon waveguide and measure its phase fluctuations at the output. We observe mechanical resonances around 8 GHz with a scattering efficiency of $10^{-5} \, \text{m}^{-1}$ and a signal-to-noise ratio of 2. The observations are in agreement with a theory of noise in these waveguides as well as with stimulated measurements. Our scheme may simplify measurements of mechanical signatures in nanoscale waveguides and is a step towards a better grasp of thermal noise in these new continuum optomechanical systems.

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Raphaël Van Laer, Christopher J. Sarabalis, Roel Baets, Dries Van Thourhout, Amir H. Safavi-Naeini. 2016-11-04. Thermal Brillouin noise observed in silicon optomechanical waveguide. https://doi.org/10.1088/2040-8986%2Faa600d

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