Group IV Mid-Infrared Photonic Devices and Applications

We present our recent results on mid-infrared photonic devices, including component optimisation, circuit design and their application to sensing. We show the performance of an on-chip FTIR microspectrometer implemented in silicon-on-insulator. A self-referenced switching sensor improves noise rejection by a factor of 11 compared to a regular waveguide sensor. We demonstrate waveguides with single-moded guidance over an octave of frequency at mid-infrared wavelengths to enable on-chip spectroscopy by suppressing higher-order modes. We apply a noise model to evaluate the performance of our waveguide sensors for therapeutic drug monitoring. Flip-chip bonding has been used to integrate quantum cascade lasers onto a GoS platform and we report further advances in coupling efficiency, structural integrity, process design and real-time laser monitoring. Finally, we discuss recent progress on detectors, included bolometers and defect-mediated methods.