A new approach to the wavelength nonuniformity problem of silicon photonic microrings

Light modulators and switches based on silicon photonic microrings can be fabricated with the conventional CMOS technology. For the first time, an optical interconnect integrated on a VLSI electronic die can be realistically envisioned. In spite of this exciting development, there is still one fundamental problem that must be overcome: wavelength nonuniformity, which is a result of miniaturization of the ring and the precision limit of the current fabricating process. Existing electronic or thermo-optical tuning methods are simply not scalable. An approach that combines techniques from both the device and architecture point of view is presented in this paper. It intends to show how the device-level wavelength nonuniformity problem can be tackled at the architecture level. An analytical model is also developed for evaluating the probability of finding a common wavelength among multiple microring resonators. The model can provide useful insights into the design of any microring-based interconnection network.