Hybrid SPAD/PD Receiver for Reliable Free-Space Optical Communication

Abstract

Free-space optical (FSO) communication provides wireless optical connectivity with high data rates and low-cost implementation; however, its performance is strongly influenced by the power attenuation due to the infrequent adverse weather conditions. This paper proposes a novel highly sensitive dual-mode receiver comprising an array of single-photon avalanche diodes (SPADs) and a PIN photodiode (PD) to enhance the availability of FSO links. In adverse weather conditions, the receiver operates in the SPADmode; whereas, in the clear weather conditions, the receiver works in the PD-mode. A hybrid receiver controller is employed in the proposed receiver to adaptively control the switching process based on the received light levels. The adaptive controller also adjusts the incident photon rate of the SPAD array using a variable optical attenuator (VOA) to optimize the performance of the SPAD unit. Our extensive performance analysis illustrates the superior achievable data rates of the proposed receiver under various weather conditions compared to the traditional FSO receivers with either PD or SPAD array.

Inter-Symbol Interference and Silicon Photomultiplier VLC Receivers in Ambient Light

“…The polarizer was then used to vary the irradiance from the transmitter falling on the SiPM until a particular BER was achieved. The existence of a range of forward error correction codes [8] and desirable BERs after correction means that the performance of VLC systems have previously been reported at BERs of 10 -3 [9], 2×10 -3 [3] and 3.8×10 -3 [10,11]. Since lower BERs are more difficult to achieve the results in Fig 4 were obtained with a BER of 10 -3 .…”

SPAD-Based Optical Wireless Communication with Signal Pre-Distortion and Noise Normalization

“…The received photon rate which gives the highest detected photon count, also known as the saturation point, is given by 1/T d [10]. A peak received power constraint can be put to limit the received photon rate below this saturation point, i.e.,…”

“…For instance, by using the off-the-shelf SPAD receiver, an achievable data rate of more than 2 Gbps with BER of 10 −3 is demonstrated in [8]. Some other works also investigate the application of SPAD-based receivers in underwater wireless optical communication (UWOC) [3], [9], free-space optical communication (FSO) [10], and vehicular optical communication [11].…”

“…In addition, the SPAD receiver with variable optical attenuator which can adaptively control the incident photon rate of the SPAD array is investigated in [10]. However, all these techniques require additional hardware at the receiver which inevitably increases the complexity of the receiver design.…”

Time-Gated Photon Counting Receivers for Optical Wireless Communication

“…Note that since the considered two segments are non-adjacent and hence with interval larger than T d , the detected photon counts in these two segments are independent. Therefore, (20) can be simplified as the product of two integrals For case (c), the correlation function can still be presented as (18); however, since the photon rate before the beginning of the first segment is not fixed at λ, the conditional probability of no arrival during (s 1 − T d , 0) does not simply equal to e −λ(T d −s1) but equals to e −λG(s1) with G(s) given in (4). Therefore, the correlation function for this case can be expressed as…”