Stimulated Brillouin scattering in integrated ring resonators

© 2017 Optical Society of America. We investigate stimulated Brillouin scattering (SBS) in ring resonators that exhibit linear and nonlinear losses. We present both analytic and numerical tools that can be used to compute the amplification and lasing threshold for the SBS-induced Stokes line. We show that, for both linear and nonlinear losses, there is a maximum achievable SBS amplification, and we show how this depends on the parameters of the ring and on the material parameters. We also study the relation between the critical coupling and input pump power to achieve amplification in various situations. We present simplified models that can be used to accurately predict the nonlinear behavior of the ring and consequently estimate the pump power required to achieve the optimum gain in a range of technologically important situations

Stimulated Brillouin scattering in silicon/chalcogenide slot waveguides

© 2016 Optical Society of America. We study slot waveguide geometries, comprising a combination of soft glasses and high-index guiding structures, for enhancing stimulated Brillouin scattering (SBS). We show that strong optical and acoustic mode confinement in these waveguides can lead to a substantial increase in SBS gain, comparable to or greater than recently proposed suspended silicon nanowire structures. We compute the optimal parameters of the structure and examine the physics of optical and acoustic confinement within slot waveguides. Finally, we compute the effects of linear and nonlinear loss mechanisms on optimum pump/Stokes powers and waveguide lengths

Lasing in ring resonators by stimulated Brillouin scattering in the presence of nonlinear loss

© 2017 Optical Society of America. We theoretically investigate lasing due to stimulated Brillouin scattering in integrated ring resonators. We give analytic expressions and numerical calculations for the lasing threshold for rings in the presence of for both linear and nonlinear loss. We demonstrate the operation of the ring in the different regimes of amplification and lasing, and show how these regimes depend on the coupling to the ring and on the nonlinear parameters. In the case of nonlinear losses, we find that there can exist an upper threshold to the lasing regime where the losses are dominated by free-carrier absorption. We also find that nonlinear losses can inhibit Brillouin lasing entirely for certain ranges of coupling parameters, and we show how the correct ranges of coupling parameters can be calculated and optimized for the design of integrated Brillouin lasers