A high-resolution low-cost time-to-digital converter (TDC) technique has been developed utilising low-cost off-the-shelf field programmable gate array (FPGA) technology. This TDC allows for the measurement of events to picosecond accuracies across many channels. A resolution of 1ps, an accuracy of 12ps RMS (single channel) and differential and integral nonlinearity figures of <±1 have been demonstrated, far outperforming linearity and resolution figures of competing techniques and technologies.

In addition to this cutting edge converter linearity, an on-chip Time Correlated Single Photon Counting (TCSPC) will be developed and demonstrated in the laboratory, allowing for correlations to be performed in real-time rather than post-processing, a key enabler for many imaging systems such as wide-field TCSPC and automotive LiDAR where real-time processing is fundamental to their widespread adoption.

In regard to the team for this project, Dr. Richard Nock holds a PhD in photon counting techniques from the University of Bristol and is a Lecturer in Electronic, Electrical and Power Engineering at Aston University. Richard has considerable experience of FPGA based time to digital converters, photonics instrumentation and data acquisition systems. The output of his PhD research led to a Royal Academy of Engineering enterprise fellowship and he was responsible for developing the electronics for the world’s first reference frame independent quantum key distribution system at the University of Bristol, a project funded by Nokia.

Dr. Xiao Ai holds a PhD in optics and LiDAR systems from the University of Bristol. Xiao has extensive experience in LiDAR and quantum instrumentation built up over the past 7 years in academia and industry (QinetiQ). Dr. Ai was awarded a QTEC Enterprise Fellowship and has started up Quantum Light Metrology (QLM) to commercialise cutting-edge novel single photon gas sensing and automotive LiDAR systems.

This project aims to further develop this fundamental breakthrough to the point of experimental proof in the laboratory, achieving technology readiness level 3 or more. Subsequent to this, an evaluation of the systems potential for use in automotive LiDAR will be performed.

This leads to the first objective to further develop and analyse the novel timing technique that from initial experiments already outperforms competing FPGA techniques in terms of linearity and resolution. Following on from this, the second objective is the creation of a TDC hardware platform with a minimum of 32 input channels and 8 output channels. The third objective is to develop a hardware TCSPC capable of running 8 correlations concurrently, to demonstrate that processing for real-time imagining systems is feasible on a FPGA. The final objective is a collaborative effort with Bristol start-up QLM to evaluate the performance of the instrumentation as a scientific instrument and as a component in their novel gas-sensing and automotive LiDAR systems.