Patent
Locally nulled sine-wave total power alarm for intrusion detecting optical communications systems
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TLDR
In this paper, an intrusion detection optical communication system modifies the original data signal to include a synchronizing periodic waveform, and the receiver generates an inverted synchronizing waveform signal corresponding with the transmitted signal to null the same under normal operation.Abstract:
An intrusion detection optical communication system modifies the original data signal to include a synchronizing periodic waveform. The receiver generates an inverted synchronizing periodic waveform signal corresponding with the transmitted signal to null the same under normal operation. When an intrusion in the optical system arises, power is extracted from the system and the nulled condition is disrupted. The disruption is detected and activates an alarm circuit when the disruption is above a threshold value.read more
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References
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Patent
Multi-core optical communications fiber
TL;DR: In this paper, the authors describe a multi-core optical communications system with a concentric multichannel optical fiber having an inner core for information and an outer core for transmitting a security signal.
Patent
Secure optical communication components, method, and system
TL;DR: In this paper, a transmitter of information to be communicated in secure form is optically coupled to a composite optical fiber at one end, the fiber being connected to a receiver of the secure information at the other end.
Patent
Secure fiber optic data transmission system
TL;DR: In this paper, a fiber optic data transmission system is protected against external physical intrusion by obscuring the data in the natural quantum noise and then limiting access to the intruder by means of an optical power alarm.
Patent
Combined intrusion sensor line
TL;DR: In this article, a single composite cable is deployed between adjacent monitoring stations r sensing an intruder, and a number of piezoelectric elements disposed in the cable provide electrical intrusion signals when they are disturbed.
Patent
Intruder alarm arrangement for an optical communication system
TL;DR: In this article, an intelligence modulated optical beam is injected into an optical waveguide through a beam splitter, and a replica of the intelligence of the injected optical beam delayed an amount equal to the round trip transit time of the optical beam was supplied as the other input of the correlator.