A Review on the Applications and Challenges of Active Silicon Ring Resonators

Integrate photonic devices show promise not only for short-range optical interconnects, but also as a platform for non-von Neumann or "neuromorphic" computing [1]-[5]. Among other devices, silicon ring resonators provide a platform for the interaction of photons, phonons and free carriers using Kerr and free-carrier nonlinearities [5]-[7]. This interesting platform has been proposed for several applications, like the realization of free carrier oscillators, bistable behaviour, nonlinear thresholder, and spike generators [5]-[10]. Compared to other CMOS-compatible materials, silicon waveguides have a low threshold for Kerr nonlinearity in telecom wavelengths. However, in this regime, two-photon absorption results in the generation of carriers. These carriers accumulate and increase the waveguide loss due to free-carrier absorption.