Athermal photonic devices for absolute distance measurement

High-precision range metrology is fundamental for precision manufacturing in aerospace, robotics, automation, and high-value manufacturing with computer-controlled machinery. The application of frequency scanning interferometry (FSI) to long-range (>1 m) high-speed (100,000 coordinates per second) absolute distance measurement is currently impractical at reasonable cost.

This is due to the extremely high modulation frequencies (typically 100 GHz or more) that require expensive data acquisition boards. Dr Ruiz's lab at Loughborough University proposed a solution based on adaptive delay lines (ADL) that can reduce the required signal sampling rate by orders of magnitude, thus paving the way for the use of fast sweeping sources such as vertical-cavity surface-emitting lasers.

Silicon photonics is an ideal platform that Dr Ruiz's lab explored for ADLs, but current devices are sensitive to temperature variations and require periodic calibration to perform accurate frequency-to-range conversion.

Our project is part of an established research and development pipeline. It aims to investigate 'athermal' photonic devices and develop solutions to provide a thermally stable length reference on a photonic chip for high-precision metrology applications.