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Title: Optical communication through the atmosphere
Author: Lock, Richard C.
ISNI:       0000 0001 3611 9351
Awarding Body: University of Surrey
Current Institution: University of Surrey
Date of Award: 1978
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An engineering study has been made of the principles involved in point-to-point communication systems operating through the atmosphere. Gallium arsenide light emitting diodes and laser diodes have been used for the radiation sources operating in the near infrared. The factors that influence the performance of these links have been discussed, and the various trade-offs of the parameters involved in their design and operation have been examined. A theoretical analysis of suitable modulation systems has been carried out with the specific aim of minimising the transmitter power consumption. An audio bandwidth link has been designed and built to test the results of the analysis, when applied to a specific performance specification. This audio bandwidth link has been operated continuously for a period of over two years to examine just how well an optical link will perform when subjected to varying atmospheric conditions. Semi-unattended monitoring equipment, designed and built for the purpose, has enabled continual measurements to be made of the link's performance throughout the period of the tests. Using results and experience from the low-powered transmitter audio bandwidth link, a video bandwidth link has been designed and built, capable of transmitting broadcast quality television signals. This included a study of methods for driving a GaAs laser diode with a suitably high pulse rate and current pulse amplitude. One solution to this problem has been used for the link. The data obtained from the prolonged tests allows an estimate to be made of how well a link might be expected to perform. The results show that the reliability of these links is considerably greater than is generally believed.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available