All-Optical Signal Processing WITH Nonlinear Resonant Devices

All-optical signal processing is of high interest in view of potential applications in long-haul high-speed communication networks. One of the key techniques is based on active or passive nonlinear Bragg gratings with and without a tapering of the bandgap. Applications envisaged are all-optical switches, limiters, and isolators. For wavelength conversion, four-wave mixing (FWM) can be used, and resonant field enhancement is exploited to improve the conversion efficiency. We investigate the isolating properties of active and passive nonlinear Bragg gratings, and we discuss FWM in passive Bragg gratings and nonlinear ring resonators. For an InP-based micro-ring resonator we report a measured record efficiency of -32.6 dB for an on-chip pump power of 13.3 dBm