A range of unique capabilities in optical and microwave signal processing
have been demonstrated using stimulated Brillouin scattering. The desire to
harness Brillouin scattering in mass manufacturable integrated circuits has led
to a focus on silicon-based material platforms. Remarkable progress in
silicon-based Brillouin waveguides has been made, but results have been
hindered by nonlinear losses present at telecommunications wavelengths. Here,
we report a new approach to surpass this issue through the integration of a
high Brillouin gain material, As2S3, onto a silicon chip. We fabricated a
compact spiral device, within a silicon circuit, achieving an order of
magnitude improvement in Brillouin amplification. To establish the flexibility
of this approach, we fabricated a ring resonator with free spectral range
precisely matched to the Brillouin shift, enabling the first demonstration of
Brillouin lasing in a silicon integrated circuit. Combining active photonic
components with the SBS devices shown here will enable the creation of compact,
mass manufacturable optical circuits with enhanced functionality