Intrusion detection and location system for use on multimode fiber optic cable
US7333681B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Aug 1, 2006 |
| Grant date | Feb 19, 2008 |
| Priority date | — |
| Expiry date | Aug 12, 2026 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG02B6/24
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
A telecommunications multimode optical fiber is secured against intrusion by detecting manipulation of the optical fiber prior to an intrusion event. Pulses are injected using a launch arrangement which generates a narrow spectral width, under-filled, non-uniform mode field power distribution in the multimode optical fiber and Fresnel reflections and Rayleigh backscattering from the pulse are detected at the transmit end to monitor the modal power distribution in the fiber which changes on manipulation of the fiber. The Rayleigh backscattering time sliced data can be stored in a register until an intrusion event is detected. The detection is carried out by a modal power distribution detection system which includes an optical coupler to tap off a portion of the light which contains the higher order signal modes.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.