Design and simulation of silicon microring optical routing switches

Using two-dimensional (2-D) scattering matrix theory, the switching behavior of inplane waveguided 2 /spl times/ 2 resonant optical switches in silicon-on-insulator was analyzed at the 1.33, 1.55, and 10.6 /spl mu/m wavelengths. The switch consisted of two straight bus waveguides coupled independently and laterally to a pair of microring resonators. Switching actuated by a /spl Delta/n + i/spl Delta//spl kappa/~ complex index perturbation of the rings was investigated. The switching effects discussed include the free-carrier-plasma dispersion, Franz-Keldysh, quantum-confined Stark, Kerr, and thermooptic effects. Each effect has its /spl Delta//spl kappa/~//spl Delta/n signature. For waveguides /spl les/0.3/spl lambda/ wide, an optimum switch design was determined in the weak coupling regime. Complete switching was found for /spl Delta/n/spl sim/2/spl times/10/sup -3/, together with significant modulation for /spl Delta/n in the 10/sup -4/ range.