McMaster University

Purpose

This project focuses on the development of single-photon avalanche detector (SPAD)-based detection system and Kramer-Kronig optical receiver for free space optical (FSO) systems. The SPAD detection systems based on low-cost, high-reliability mainstream silicon technologies will be developed. In principle, SPADs can detect a single photon and so are expected to be the most sensitive detector for FSO systems. The end result of this proposed work will be the optimum SPAD detection system. Currently, FSO systems employ direct-detection receivers in which photo-current is proportional to optical intensity and hence, the phase of optical signal is lost. In this project, the team will extract the phase of optical signal from intensity using a Kramer-Kronig receiver. This additional degree of freedom enables to modulate the phase of the optical carrier which enhances the data rate of FSO system. The extra-information provided by the optical phase enables the accurate channel compensation helping to improve performance.