High nonlinear figure-of-merit amorphous silicon waveguides.

The nonlinear response of amorphous silicon waveguides is reported and compared to silicon-on-insulator (SOI) samples. The real part of the nonlinear coefficient γ is measured by four-wave-mixing and the imaginary part of γ is characterized by measuring the nonlinear loss at different peak powers. The combination of both results yields a two-photon-absorption figure of merit of 4.9, which is more than 7 times higher than for the SOI samples. Time-resolved measurements and simulations confirm the measured nonlinear coefficient γ and show the absence of slow free-carrier effects versus ns free-carrier lifetimes in the SOI samples.

Low TPA and free-carrier effects in silicon nanocrystal-based horizontal slot waveguides.

We present the characterization of the ultrafast nonlinear dynamics of a CMOS-compatible horizontal-slot waveguide with silicon nanocrystals. Results are compared to strip silicon waveguides, and modeled with nonlinear split-step calculations. The extracted parameters show that the slot waveguide has weaker carrier effects and better nonlinear figure-of-merit than the strip waveguides.

Characterizing and modeling backscattering in silicon microring resonators.

We present an experimental technique to characterize backscattering in silicon microring resonators, together with a simple analytical model that reproduces the experimental results. The model can extract all the key parameters of an add-drop-type resonator, which are the loss, both coupling coefficients and backscattering. We show that the backscattering effect strongly affects the resonance shape, and that consecutive resonances of the same ring can have very different backscattering parameters.