Reliable Optical Receiver for Highly Dynamic Wireless Channels: An Experimental Demonstration

Optical wireless communication (OWC) has attracted more and more attention in recent decades. One promising method of improving the sensitivity of the receivers in OWC system is the utilization of the single-photon avalanche diode (SPAD). However, due to the non-linear effects induced by the dead time, the performance of SPAD-based receivers is significantly degraded in high incident power regime. Recently, we proposed a novel hybrid SPAD/PD receiver in which the receiver can adaptively switch between the SPAD- and PD-mode based on the instantaneous received optical power. In addition, a variable optical attenuator (VOA) is applied to optimize the performance of the SPAD unit. In this work, the superiority of the proposed hybrid receiver is experimentally demonstrated. For a data rate transmission of 450 Mbps, it is demonstrated that the proposed receiver significantly outperforms the traditional PD and SPAD array receiver in terms of the BER performance and can greatly extend the receiver dynamic range to reliably operate at both extremes of the incident light levels.