Characterization of efficient wavelength conversion by four-wave mixing in sub-micron silicon waveguides

We characterize silicon waveguide based wavelength converters using a commercial semiconductor optical amplifier (SOA) based wavelength converter as a benchmark. Conversion efficiency as high as -5.5 dB can be achieved using a 2.5 cm long sub-micron silicon-on-insulator rib waveguide. Comparison with the SOA reveals that silicon offers broader conversion bandwidth, higher OSNR, and negligible channel crosstalk. The impact of two-photon absorption and free carrier absorption on the conversion efficiency and the dependence of the efficiency on the rib waveguide dimensions are investigated theoretically. Using a nonlinear index coefficient of 4x10(-14) cm(2)/W for silicon, we obtain good agreement between simulations and measurements.