摘要：利用“光”进行信息的传递自古有之，早在公元前700多年前我国古代就在战争中利用烽火台进行火光通信。在电话出现之后，人们开始了用光进行通信的可行性研究。从贝尔发明光电话到“二战”，光通信使用的都是热光源，是非相干光，它们调制困难，通话质量差，传输过程中损耗也很大，这对光通信的发展和应用存在诸多限制。直到激光技术的出现，在很大程度上促进了光通信领域的发展。而水下无线光通信的发展，在战术监视、海洋研究、污染监测、海洋勘探、石油的管理和维护、气候变化监测等远海和近海研究领域具有许多潜在的应用价值。然而，水下无线通信的最大挑战来源于海洋或海水是个复杂的物理化学生物系统以及其自身固然存在的流动性，这就使得海水的基本特性复杂多变。信息在传输过程中必然会有损耗，激光在水下的传输也会由于复杂的水下环境产生衰减。在本文中，主要的关注点是激光在水下传输过程中由于散射所引起的衰减。通过查阅相关文献，了解海水的散射系数，借助Matlab软件仿真得出海水的衰减特性曲线。通过仿真数据可以得出，激光波长与海水的散射系数呈负相关，与海水总的衰减特性呈正相关。此研究成果能够对水下激光通信的相关研究作出一定的参考价值，以及后续的水下通信研究提供可能的帮助。

关键词：水下无线光通信；散射系数；衰减特性

Abstract:"light" used to the transmission of information in the ancient times. As early as 700 BC years ago, the ancient Chinese used the beacon to communication in the war. That using  light to communicate were studied after the telephone appeared. About Bell and the "World War II", hot light sources, non-coherent light, were used in optical communication. The disadvantages of optical communication are difficult modulation, poor communication quality and great transmission loss. These lead to many restrictions to the development and  application of optical communication. Until the emergence of laser technology, optical communications has been developed greatly. The development of underwater optical wireless communication has potential applications in many fields, such as tactical surveillance, ocean research, pollution monitoring, marine exploration, oil management and maintenance, and climate change monitoring. However, the biggest challenge is the complex physical and chemical biological system for marine or seawater in underwater wireless communications. Moreover, it is the mobility of seawater that makes the basic characteristics of seawater are complex and changeable. Information in the transmission process is bound to loss, laser transmission in the water will be suffered from attenuation because of complex underwater environment.  The main topic of this paper is the attenuation of the laser that mainly caused by scattering during the underwater transmission. The seawater’s scattering coefficient can be calculated according to the relevant literature. Matlab simulates the characteristics curve of seawater attenuation. It can be concluded that laser wavelength with the scattering coefficient of seawater is negatively correlated and positively correlated with the total attenuation characteristics of seawater, respectively. The results of this study can provide some reference value for the related research of underwater laser communication, as well as follow-up underwater communication research to provide possible help.

Keywords: underwater optical wireless communication; scattering coefficient; ; attenuation characteristics

目录

第一章 绪论