Single-photon detection for MIMO underwater wireless optical communication enabled by arrayed LEDs and SiPMs

Abstract

Underwater wireless optical communication (UWOC) is a promising technology that can be a candidate to improve the communication capacity and speed in aquatic media. The aim of this study is to examine the performance of a silicon photomultiplier (SiPM) array-based multiple-input multiple-output (MIMO) UWOC system. A SiPM is a modern solid-state photodetector with extremely high sensitivity up to the single-photon level or a photon-counting ability, which helps in detecting extremely weak light signals after long-distance underwater channel attenuation. We clarify the basic characteristics and photon-counting detection mode of a SiPM. In particular, the photocount of a SiPM is approximated by a Gaussian distribution, and theoretical analysis shows that only 13.3 photons need to be detected during “1” symbol period to achieve a bit error rate of 10−3 in an ambient light environment. Moreover, a SiPM also has a better analog mode detection ability than an avalanche photodiode (APD) and realizes 2 Mbps analog communication owing to its unique array structure and high photon detection efficiency. Furthermore, MIMO, i.e., spatial diversity, is applied as an effective method to relax the link alignment, improve the system performance, and alleviate the effect of optical turbulence. In our experiment, with a photon-counting 6×3 MIMO scheme, an energy per bit of 7.38×10−9 J/bit is achieved at a scintillation index of 4.66×10−3 in a 10 m water tank with 1 Mbps on-off-keying (OOK) modulation. To the best of our knowledge, this is the first study on a MIMO-UWOC system based on the photon-counting mode of a SiPM array. This UWOC system combines the advantages of SiPMs and the MIMO scheme and has the potential to realize long-distance UWOC under optical turbulence.

Improved Synchronization Scheme for the Photon- Counting-Based Underwater Optical Wireless Communication System

“…In a photon-countingbased UOWC system, the Poisson model can well characterize the number of received photons during each symbol period. Specifically, assuming the sync word starts from symbol position n + 1 and phase k in the received signals, the probability of r n+i,k given the transmitted symbol x i in the i-th symbol period is [17]- [19] Pr(r n+i,…”

Multilevel Simultaneous Lighting–Imaging System

“…With the advent of the era of high-speed communication, optical communication technology, a supplementary means of communication, has also made great progress. − The information exchange in this work is based on light, so it is suitable for the experimental scheme of traditional optical communication. In terms of hardware, we can carry out dual-function simultaneous driving of the emission and detection mode. − In terms of software, we can explore the signal restoration algorithm. − However, these findings fall short of the next generation of smart screens because the binarization of detection values leads to a quantization order for imaging grayscale that is too small, which is a problem that we have not discussed previously.…”

Toward Automatic Subsea Operations Using Real-Time Underwater Optical Wireless Sensor Networks

“…In contrast, underwater wireless optical communication (UWOC) technology is a promising candidate for real-time, high-speed (up to ~Gb/s), and short-distance (up to ~100 m) communication among swarms of underwater equipment thanks to its high bandwidth and low latency [8]. However, most of the prior work focused on the physical layer of point-to-point UWOC [8][9][10][11][12].…”