An optical system for line-of-sight communication

Thesis (M. Eng.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2009.Includes bibliographical references (p. 95).We design and implement a system for short and medium range directional two-way wireless communication. The system uses infrared radiation to transmit and receive voice data digitally. We utilize narrow angle infrared light emitting diodes for transmission, directed across a reasonable angular range that allows the system to transmit across a narrow beam to the receiver, avoiding the dangers of detection, jamming, and eavesdropping that traditional omnidirectional radio transmission entails. On the receiving end, a wide-angle detector is used. The system is integrated inconspicuously into a military vest, allowing the wearer to communicate while on the field. In the working version of this system we use traditional semiconductor photodetectors and receivers. We also investigate the properties of optoelectronic fibers, novel semiconductor devices that can act as line detectors of light. We characterize these fibers, and analyze their potential for use as photodetecting devices in this system.by Agustya R. Mehta.M.Eng