Mission

We will demonstrate broadband Si and Ge-based passive devices (splitters, couplers, resonators, interferometers) with low insertion loss in the 3-14µm range. Such devices will utilise our unique suspended Si and Ge approach based on subwavelength grating (SWG) claddings, using the full transparency ranges of Si and Ge. We will optimise mechanical integrity and the application of suitable claddings and optimised phase shifters for MIR sensor development. To date, Si and Ge MIR chips have been fabricated using e-beam lithography, but for mass manufacturing compatibility, it is important to address wafer scale fabrication using our deep UV (DUV) lithography system. We will also develop a novel “on-chip integrating sphere” geometry both in Si and Ge that promises ultralong interaction lengths. To improve signal-to-noise (S/N) ratio we will develop Si and Ge photonic circuits with on-chip referencing and on-chip modulation.

We will develop a range of devices for integration with Si and Ge platforms to enable on-chip spectroscopy and sensing. We will develop quantum and interband cascade lasers (QCL, ICL) with broad tuning range and will use optimised integration techniques including elastomer stamp transfer and flip-chip transfer for integration into waveguide-based spectrometers. We will also investigate ICL/QCL-based on-chip mid-IR frequency combs, that will enable on-chip versions of comb–based spectroscopic methods that have demonstrated high resolution/sensitivity and fast parallel acquisition times in benchtop applications. We will also explore broad-band spectroscopic techniques based on MIR intraband LEDs which have recently shown excellent power and bandwidth properties. In terms of detectors, we will work on novel room temperature waveguide microbolometers that can be wavelength-selective and highly sensitive via resonance enhancement. In addition, III-V detectors will be developed for Si and Ge photonic circuits.

We will integrate and package components (sources/detectors, sensor components, Si and Ge chips, and sample delivery systems) and develop electronic to produce modular systems at TRL3 for functional demonstrators. Packaging (including demonstrators) will maximise robustness (particularly to vibration, fluids / particles and wide temperature / pressure variations) at the component and system level by investigating materials, interface bonding strategies, encapsulation, and mechanical design innovations (e.g. compliance, fluid encapsulation). Focus will be maintained on research by utilising existing technology.