上海科技大学知识管理系统

It is widely accepted that the optical signal rapidly attenuates to a level of few photons after being transmitted over several hundred meters in seawater due to the strong absorption and scattering effects. Therefore, underwater wireless optical communication based on photon-counting detectors has become a hot research topic to increase the energy efficiency and the corresponding communication range. Although there are some reports on system simulation and experimental testing, there is no comprehensive analysis of long-distance channels in the clearest deep sea waters to achieve the potential longest communication range. In this paper, a deep-sea long-range wireless photon-counting communication system is established. The blue-green narrow-beam lasers, commercial photon-counting detectors and the serially concatenated pulse position modulation are adopted. Then, aiming at the clearest deep sea optical channel, the Monte Carlo simulation method is employed and the impulse responses within 800-m are obtained. Finally, numerical results show that the delay spread is negligible in the long-distance channel and the wireless photon-counting communication performs excellently in deep sea environments. Using a 440-nm laser with an average power of 5 W and a 35-cm receiving aperture, a communication distance of 1000 m can be achieved with data rates of several tens of kbps and a bit-error-rate below 10(-8).