Long-reach underwater wireless optical communication with relaxed link alignment enabled by optical combination and arrayed sensitive receivers

Abstract

To extend the transmission distance and relax the strict alignment requirement of underwater wireless optical communication ((UWOC), we design and implement a UWOC system using a 3×1 fiber combiner and a high-sensitive multi-pixel photon counter (MPPC). The 50-m and 100-m transmission distances (corresponding to 24 attenuation lengths) are experimentally achieved with the data rates of 16.78 Mbps and 8.39 Mbps, respectively, in a 50-m standard swimming pool. Moreover, we also investigate and optimize the performance of misalignment tolerance of this system using two MPPCs as the detectors together with different diversity reception technologies. At the 50-m transmission distance, the maximum offset between the MPPC array and the light spot center can be extended to 9 m using the maximal ratio combining (MRC), while the maximum offset is 6 m when using single MPPC.

Quantum characteristics and applications of multi‐pixel photon counter

“…In addition, in the underwater wireless optical communication application, the high sensitivity of MPPC ensures high efficiency and robustness of the system and the multi-pixel characteristic makes the system require less alignment of transmitter and receiver. 26 Another straightforward application of MPPC is to verify the multiphoton quantum states of the incident light, especially for non-classical states. Besides coherent states and multi-mode thermal light, 27 the detection of single-mode squeezed vacuum states 5 and two-mode squeezed vacuum states 28 have been achieved by employing MPPC.…”

“…Moreover, a QRNG of multi‐bit true random numbers and a QRNG with high random bit generation rate 99.82 Mbit/s are demonstrated in References 24 and 25, which are more prospective in quantum key distribution. In addition, in the underwater wireless optical communication application, the high sensitivity of MPPC ensures high efficiency and robustness of the system and the multi‐pixel characteristic makes the system require less alignment of transmitter and receiver 26 …”

50 m/187.5 Mbit/s real-time underwater wireless optical communication based on optical superimposition

“…Underwater wireless optical communication (UWOC) has the advantages of high data rate and low latency, but with the shortcomings of strict link alignment and limited transmission distance [1][2][3][4] . The blue laser diode (LD), with high power, is gradually becoming the mainstream as the light source in the long-distance UWOC system [5][6][7][8][9][10] . Besides, many researchers employed high-sensitivity optical detectors such as a multi-pixel photon counter (MPPC), single-photon avalanche diode (SPAD), and photomultiplier tube (PMT) as receivers to detect weak optical signals [6][7][8][9][10][11] .…”

Diffractive deep neural network based adaptive optics scheme for vortex beam in oceanic turbulence

“…In recent years, underwater wireless optical communication (UWOC) has attracted a lot of attentions due to its high data rate, high security, high bandwidth, low latency, and low cost [1][2][3][4]. UWOC has many applications in the rapidly growing human underwater activities, such as submarines, autonomous underwater vehicles and unmanned underwater vehicles [5,6].…”