Power-efficient calibration and reconfiguration for on-chip optical communication

On-chip optical communication infrastructure has been proposed to provide higher bandwidth and lower power consumption for the next-generation high performance multicore systems. Online calibration of these optical components is essential to building a robust optical communication system, which is highly sensitive to process and thermal variation. However, the power consumption of existing tuning methods to properly calibrate the optical devices would be prohibitively high. We propose two calibration and reconfiguration techniques that can significantly reduce the worst case tuning power of a ring-resonator-based optical modulator: 1) a channel re-mapping scheme, with sub-channel redundant resonators, which results in significant reduction in the amount of required tuning, typically within the capability of voltage based tuning, and 2) a dynamic feedback calibration mechanism used to compensate for both process and thermal variations of the resonators. Simulation results demonstrate that these techniques can achieve a 48X reduction in tuning power - less than 10W for a network with 1-million ring resonators.