150 m/500 Mbps Underwater Wireless Optical Communication Enabled by Sensitive Detection and the Combination of Receiver-Side Partial Response Shaping and TCM Technology

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] .…”

“…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] .…”

“…In 2021, a full-duplex UWOC system was demonstrated, reaching a data rate up to 200 Mbit/s at a distance of 100 m [7] . In the same year, a joint DSP scheme including partial response shaping and trellis-coded modulation technology was proposed and employed in a UWOC system, which successfully achieved a data rate of 500 Mbit/s with a transmission distance up to 150 m [8] . Besides, the sparse Volterra equalizer, which can effectively reduce the computational complexity, was developed for the UWOC system to realize a data rate of 500 Mbit/s in a 200 m underwater transmission [9] .…”

“…Spatial summing is effective in improving the performance, which has been widely used in the visible light communication (VLC) system to mitigate the nonlinear effect. [12] LD/APD 60 (tap water) / / 2.5 Gbit/s OOK AWG/OSC 2019 [5] LD/APD 56 (tap water) 0.0876 m −1 4.9056 3.31 Gbit/s QAM AWG/OSC 2020 [13] LD/MPPC 100 (pool water) 0.24 m −1 24 8.4 Mbit/s OOK AWG/OSC 2020 [6] LD/PMT 100 (pool water) 0.0585 m −1 5.85 200 Mbit/s OOK AWG/OSC 2021 [7] LD/PMT 150 (pool water) 0.053 m −1 8.775 500 Mbit/s PAM AWG/OSC 2021 [8] LD/PMT 200 (pool water) 0.0325 m −1 6.5 500 Mbit/s PAM AWG/OSC 2021 [9] LD/PMT 100.6 (tap water) 0.0658 m −1 6.6195 3 Gbit/s OOK AWG/OSC 2022 [10] LD/PMT 5 (turbid water) / / 10 Mbit/s PPM FPGA 2016 [14] LD/PIN 3 (artificial seawater) 0.481 m −1 1.443 50 Mbit/s QAM FPGA 2019 [15] LED/PIN 1.2 (tap water) / / 2.34 Gbit/s DMT FPGA 2020 [16] LED/APD 10 (tap water) 0.056 m −1 0.56 1 Mbit/s FSK FPGA 2020 [17] LD/APD 3.6 (tap water) / / 2.2 Gbit/s OFDM FPGA 2020 [18] LD/SPAD 2 (tap water) / / 6.21 Mbit/s PPM FPGA 2021 [11] LD/PMT 50 (pool water) 0.1307 m −1 In 2013, a VLC transmitter employing discrete power level stepping was proposed to address the nonlinearity, restricted dynamic range, and complex system designs of the conventional optical transmitters [22] . In 2017, a highly compact array of micro-LED pixels was proposed to generate a discrete optical signal, which achieved a data rate up to 200 Mbit/s [23] .…”

Experimental Demonstration of 55-m / 2-Gbps Underwater Wireless Optical Communication Using SiPM Diversity Reception and Nonlinear Decision-Feedback Equalizer

“…The commercially available PMT-based product, namely BlueComm 200 series made by Sonardyne, was designed to support a data rate of 10 Mbps over a 150-m clear water channel [17]. Employing pulse amplitude modulation with 4 levels (PAM4), Xu et al undertook the realization of a 150-m / 500-Mbps PMT-based UWOC system enabled by the combination of receiver-side partial response shaping and Trellis coded modulation [18]. Nevertheless, PMT requires careful handling as well as a high bias voltage and is susceptible to the magnetic field.…”