INTERFEROMETRIC OPTICAL FIBER DATA LINK

Abstract

An apparatus for a method for assuring the secure transmission of information between a transmitter and a receiver is fabricated along the lines of a Mach-Zehnder interferometer. Two, identical length single-mode fibers extend between the transmitter and receiver to act as transmission paths. Within the transmitter a coiled length of like single-mode fiber integrally extends from one of the fibers reaching from the transmitter to the receiver. Within the receiver a like length of like single-mode fiber integrally extends from the other end of the other fiber reaching from the transmitter to the receiver. A superradiant diode in the transmitter emits pulses of coherent wavetrains that are split and sent through the two lengths of fibers and their associated integrally connected coils. A detector in the receiver senses variations in the interference fringes when a modulator in the transmitter shifts in path length the coherent wavetrains in one of the fibers in accordance with the information desired to be transmitted. Because of the integrally extending coils in the transmitter and the receiver, an intruder to the system would be unable to find where the transmission paths are identical and hence would be unable to monitor the modulated interference fringe patterns.

Source: Google Patents

35 USC §181 Secrecy Order

Inventor

• 1DONALD J. ALBARES

Sensitive facility: San Diego CA (SAIC/General Dynamics)

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