Analysis of enhanced stimulated Brillouin scattering in silicon slot waveguides

Research paper by Raphaël Van Laer, Bart Kuyken, Dries Van Thourhout, Roel Baets

Indexed on: 23 Oct '13Published on: 23 Oct '13Published in: Physics - Mesoscopic Systems and Quantum Hall Effect


Stimulated Brillouin scattering has attracted renewed interest with the promise of highly tailorable integration into the silicon photonics platform. However, significant Brillouin amplification in silicon waveguides has yet to be shown. In an effort to engineer a structure with large photon-phonon coupling, we analyzed both forward and backward Brillouin scattering in high-index-contrast silicon slot waveguides. The calculations predict that gradient forces enhance the Brillouin gain in narrow slots. We estimate a currently feasible gain of about $10^{5} \, \text{W}^{-1}\text{m}^{-1}$, which is an order of magnitude larger than in a stand-alone silicon wire. Such efficient coupling could enable a host of Brillouin technologies on a mass-producible silicon chip.