Instantaneous microwave frequency measurement using four-wave mixing in a chalcogenide chip

We present the first instantaneous frequency measurement (IFM) system using four-wave mixing (FWM) in a compact photonic chip. We exploit the high nonlinearity of chalcogenide to achieve efficient FWM in a short 23 mm As2S3 waveguide. This reduces the measurement latency by orders of magnitude, compared to fiber-based approaches. We demonstrate the tuning of the system response to maximize measurement bandwidth (40 GHz, limited by the equipment used), or accuracy (740 MHz rms error). Additionally, we modify the previous FWM-based IFM system structure to allow for ultra-fast reconfiguration of the bandwidth and resolution of the measurement. This has the potential to become the first IFM system capable of ultra-fast accurate frequency measurement, with no compromise of bandwidth.