Abstract
In this study, we built a single photon avalanche diode (SPAD) receiver based underwater wireless optical communication (UWOC) system. The bit error rate (BER) and signal-to-noise ratio (SNR) performance of UWOC with different distances and data transmission rates were obtained. Based on the water attenuation coefficient of 0.12 m <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-1</sup> , a series of neutral density (ND) filters were exploited to attenuate the light output power from the blue laser diode (LD) to simulate the long distance UWOC. The maximum estimated distances of 144 m and 117 m with corresponding BERs of 1.89 × 10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-3</sup> and 5.31 × 10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-4</sup> at data transmission rates of 500 bps and 2 Mbps were acquired in UWOC system using on-off keying (OOK) modulation scheme, respectively. Furthermore, we compared the differences between free-space and underwater channels, and a divergence angle of ~1.02 mrad was measured experimentally at a distance of 50 m in the free space. The long UWOC distances obtained in this study partly benefit from high sensitivity SPAD, the small laser divergence angle and low light attenuation. This study provides an approach to achieve long distance UWOC using SPAD.
Highlights
High-Sensitivity and long-distance underwater wireless optical communication (UWOC) has been paid significant attention recently by lots of researchers [1]–[7]
Optical receivers typically used in UWOC systems are positive intrinsic negative (PIN) diodes and avalanche photodiodes (APDs)
We proposed and experimentally demonstrated a long-distance UWOC system based on a single photon avalanche diode (SPAD) receiver
Summary
High-Sensitivity and long-distance underwater wireless optical communication (UWOC) has been paid significant attention recently by lots of researchers [1]–[7]. On account of potential advantages of low cost, low latency and high safety, UWOC is considered to be an important alternative candidate to acoustic communications and radio frequency (RF) communications [1]–[10]. It has been proposed as an important communication technology for future applications in oceanography exploration and detection activities. Optical receivers typically used in UWOC systems are positive intrinsic negative (PIN) diodes and avalanche photodiodes (APDs). Single photon avalanche diode (SPAD) is an APD operating in Geiger-mode. SPADs can be used to detect individual photons, suitable for low-power and long-distance optical communications
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