Phase-Preserving Power Limiting Function Using InP on SoI Photonic Crystal Nanocavity

We report on the use of an InP/silicon-on-insulator hybrid photonic crystal nanocavity for the realization of a phase-preserving all-optical power limiter. This function is experimentally demonstrated with 20-Gbit/s nonreturn-to-zero quadrature phase-shift-keying signals. Histogram-based measurements of the phase distributions indicate negligible variations of the phase noise, whereas the amplitude fluctuations are suppressed, confirming the effectiveness of cavity switching for implementing the power-limiter function. Significant power penalty reduction is achieved, indicating a promising application for future photonic circuits.