SIRG: Underwater Optical Modem: The Last Hundred Meters

海洋科学正在开始一个新的阶段，在这个阶段，科学家将进入海洋环境，并使用海洋观测站自适应地观察地球-海洋系统，这些观测站提供电力和通信，以访问和操纵实时传感器网络。仪器将被插入基础设施，因此，区域传感器覆盖将需要在具有科学价值的地点周围铺设大量昂贵和耗时的电缆。随着适用于水下作业的“无线”技术的发展，这一限制可能会减少。无线双向数据链路将使自动深水潜水器能够通过互联网进行远程操作。这将允许高成本、高性能的传感器集中在几个能够以自适应方式在更大范围内运行的移动平台上。除了可见光范围外，海洋基本上对电磁辐射是不透明的，因此“无线”水下通信需要发展光学调制解调器技术。高数据速率(1-10Mbit/S或更高)可以在频谱的蓝色部分在100米数量级的范围内实现，在良好的条件下甚至更高。PI建议设计、制造、测试和验证双向光学调制解调器，该调制解调器旨在将移动深潜潜器连接到固定节点，该固定节点又通过光缆连接到海洋观测站。将支持每条电缆多个节点，从而实现相对广泛的区域覆盖。随着进一步的发展，光调制解调器技术将能够同时支持每个节点上的许多传感器，从而形成类似于蜂窝电话系统的水下网络。基础研究包括随机介质中的光传播，低功率光信号的产生，以及宽视场范围内的捕获和检测。此外，设计一种明确用于在移动车辆上运行的光通信系统提出了新的技术挑战。最后，将移动平台与海洋观测站连接起来的水下光通信技术将在包括生物、化学、物理和地质海洋学在内的广泛学科中科学地实现。

The ocean sciences are beginning a new phase in which scientists will enter the ocean environment and adaptively observe the earth-ocean system using ocean observatories that provide power and communication to access and manipulate real-time sensor networks. Instruments will be plugged into the infrastructure, and hence areal sensor coverage will require the costly and time-consuming lay of numerous cables around a site of scientific interest. This limitation could be reduced with the development of "wireless" technologies suitable for operation underwater. Wireless bi-directional data links would enable remote operation of autonomous deep vehicles over the Internet. This would allow high cost, high capability sensors to be concentrated on a few mobile platforms capable of operating over an extended region in an adaptive manner. The ocean is essentially opaque to electromagnetic radiation except over the visible light range, and hence "wireless" underwater communication requires the development of optical modem technology. High data rates (1-10 Mbit/s or more) are achievable in the blue part of the spectrum over ranges of order 100 meters, and more under good conditions. The PIs propose to design, fabricate, test, and validate a bi-directional optical modem intended to link a mobile deep submergence vehicle to a fixed node which is in turn connected to an ocean observatory by fiber optic cable. Multiple nodes per cable will be supported, enabling the coverage of relatively wide areas. With further development, the optical modem technology will be able to simultaneously support many sensors per node, resulting in an underwater network analogous to a cellular telephone system. Fundamental research includes work on optical propagation in random media, low-power optical signal generation, plus acquisition and detection over a wide field of view. In addition, devising an optical communications system explicitly for operation on a mobile vehicle poses novel technological challenges. Finally, underwater optical communications technology to link mobile platforms to ocean observatories would be scientifically enabling in a wide range of disciplines, including biological, chemical, physical, and geological oceanography.