| 摘要 |
PROBLEM TO BE SOLVED: To provide a safe optical communication system in which the luminous intensity of light is so strong that the light can be applied to long distance optical communication, and a configuration of a transmitter is simple, and furthermore, which can withstand an nonlinear optical effect of an optic fiber is strong. SOLUTION: Laser light is directly frequency modulated by a random number generated from a seed key and an information signal, and the information signal is transmitted. At this time, a frequency interval at the time of modulation is made considerably narrower than the spectrum line width of an optical source. In a receiver, light heterodyne reception is performed, and the original information signal is demodulated using a random number generated from the same seed key as that of a transmitter in the same process. COPYRIGHT: (C)2009,JPO&INPIT
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