Nonlinear pulse interaction in microresonator slow-light waveguides

Using the constraint of fixed pulse distortion, three slow-light waveguide architectures [coupled-resonator optical waveguide, side-coupled integrated spaced sequence of resonators (SCISSOR), and ring enhanced Mach-Zehnder interferometer (REMZI)] are studied for linear delay-bandwidth product, nonlinear phase shift, and nonlinear pulse interaction; pulse to pulse interaction is a limiting factor on the bit rate. For the same number of stages the REMZI architecture has the highest delay-bandwidth product and the best nonlinear sensitivity, but the SCISSOR architecture has the weakest nonlinear pulse interaction. We further define a phase efficiency factor, which represents the fraction of the total filter phase that contributes to the delay-bandwidth product. We also show that resonator loss reduces the nonlinear sensitivity and the delay-bandwidth product in the nonlinear regime.