Ultrafast chip-integrated all-optical switch in photonic circuits

We report a picosecond and low-power all-optical switch with multiple operating wavelengths in integrated photonic circuits, on-chip-triggered by a control light. The sample configuration combines the advantages of plasmonics and photonics, i.e. plasmonic nanostructures used as core units interconnected by ultralow-loss dielectric slot waveguides. A large nonlinearity enhancement is obtained based on resonant excitation, local field effect, and field enhancement effect, while fast response is maintained by intermolecular energy transfer. A fast response of 63 ps and ultralow control light intensity of 450 kW/cm² are achieved.