Backup mandate Research Council: Exploring the potential of single-photon detection in digital optical communication

Increasing trends in the demand for data access create a strong need for innovations in optical wireless and fiber communication. Three major challenges are the signal reliability in low signal-to- noise-ratio (SNR) situations, multipath fading, and multi-user scalability. In this project the single-photon avalanche diode (SPAD) is proposed as a potential solution for these problems. Compared to the state-of-the-art, they have a higher sensitivity, measure both the
photon count (light power) and the arrival time of a single photon and exhibit a digital nature, unlike other optical detectors. The first objective of this project is to exploit these characteristics to efficiently reject noise in low SNR situations. This will be done by designing multiple encoding schemes specifically operating with SPADs. As second objective, I will explore the multipath mitigation potential of
the SPAD by designing a 'rake' receiver based on ultra-wideband communication, known for its resilience to multipath fading. The third objective is to investigate how a SPAD-receiver can support a scalable multi-user system. This is done by establishing a multi-user link with the novel encoding schemes and the SPAD rake receiver. Al this will lead to new insights on how the SPAD can be used to meet major challenges in optical communication and will encourage further research and integration. On the longer term, this can result in reliable, low-cost and energy efficient communication systems.