Drastically SBS Gain Enhancement in Silicon-on-Insulator based Nano-Waveguides

Abstract:
Stimulated Brillouin scattering (SBS) is a third-order nonlinear optical process by which optical photons are coupled to acoustic phonons, i.e. two optical modes are coupled through an elastic mode. The SBS has very unique properties which makes it very attractive for a lot of applications developed in the last few years. These applications span from the measurement of the global warming to the characterisation of faults in buildings after an earthquake for instance. For optical telecommunications especially the alteration of the group velocity (Slow- and Fast Light) and the Ultrahigh-Resolution Spectroscopy - both based on SBS - are very important. For applications in optical telecommunications particularly the fiber based SBS is used. However, in optical fibers the SBS is initiated by electrostriction, which makes the effect rather low and requires kilometres of fibers to be effective. However, on the nano-scale this paradigm breaks down. In silicon-on-insulator based sub-wavelength waveguides a combination of electrostriction and radiation pressure leads to a drastically enhancement of the SBS effect by several orders of magnitude. Thus, such nano-waveguides based chips have the potential to effectively store optical packets, measure optical spectra with ultrahigh resolution, or be the building blocks of microwave photonics. Here we give an introduction and present simulation results for rectangular silicon-on-insulator based nano-waveguides suspended by air, showing the very high potential of this new field of research.