Centre for Quantum Technology

Dr Ross Millar and Prof Douglas Paul in the James Watt School of Engineering at the University of Glasgow have submitted a patent on newly developed single photon avalanche diode (SPAD) detectors using germanium on silicon that operate at short wave infrared wavelengths with superior performance to previous detectors with technology that is at least 200 times cheaper.

These SPAD detectors produced in the University’s James Watt Nanofabrication Centre through funding from EPSRC, QuantiC and Dstl from the UK Quantum Technology Programme have been used to undertake light detection and ranging (LiDAR) where a pulse of light from a laser is timed when it is released and the clock is stopped when the SPAD detects the returning photons. By knowing the time the photons travel at the speed of light to and from an object, the distance or range to the object can be calculated. With Heriot-Watt University we have demonstrated full 3D range images of objects can be produced in millisecond timescales.

LiDAR is being developed for driver aids to warn drivers of other vehicles, roadside barriers or objects in the path of their vehicle and for autonomous vehicles. Our SPADs operates at short wave infrared wavelengths which allow higher laser powers which are eye safe, have far less solar background and where light can more easily be transmitted through obscurants such as rain, fog or mist. Operation at these wavelengths around 1500 nm allows signal to noise levels for LiDAR which are over 80 times higher than CMOS SPAD operating wavelengths at 905 nm whilst the detector arrays produced on silicon should be at least 200 times cheaper than the competitor III-V technology.

We are working in the InnovateUK SPIDAR project with Toshiba Cambridge, IQE, Sivers Photonics, Bay Photonics, Thales, Horiba-MIRA and Network Rail along with the Universities of Cambridge, Edinburgh and Heriot Watt to translate the technology to UK industry and build a lidar supply chain to manufacture complete lidar systems in the UK.

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First published: 11 August 2021