Guided Acoustic and Optical Waves in Silicon-on-Insulator for Brillouin Scattering and Optomechanics
OSTP Journal Article
Stanford Univ Stanford United States
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We numerically study silicon waveguides on silica showing that it is possible to simultaneously guide optical and acoustic waves in the technologically important silicon on insulator SOI material system. Thin waveguides, or fins, exhibit geometrically softened mechanical modes at gigahertz frequencies with phase velocities below the Rayleigh velocity in glass, eliminating acoustic radiation losses. We propose slot waveguides on glass with telecom optical frequencies and strong radiation pressure forces resulting in Brillouin gains on the order of 500 and 50 000 W-1m-1for backward and forward Brillouin scattering, respectively.