Intrusion detection system for use on an optical fiber using a translator of transmitted data for optimum monitoring conditions
US7092586B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | May 26, 2005 |
| Grant date | Aug 15, 2006 |
| Priority date | — |
| Expiry date | May 26, 2025 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG02B6/4469
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
A method and system of intrusion detection system for a multimode fiber optic cable. A light signal is launched into the cable fiber to establish a narrow spectral width, under-filled non-uniform mode field power distribution in the cable. A small portion of the higher order signal modes arriving at the remote end of the cable is sampled by use of a coupler and monitored for transient changes in the mode field power distribution. The power distribution changes with physical disturbance of the cable. When those changes are detected as being characteristic of fiber intrusion, the system activates an alarm. This method can sense and alarm any attempt to access the optical fibers in a fiber optic communication cable. In preferred embodiments, the active signal of a multimode optical fiber is monitored for both signal degradation and transient power disturbance patterns that could indicate fiber damage or physical intrusion. A translator can be provided in an existing optical fiber system in which the data signals are translated in wavelength and/or launch conditions to optimize the monitoring signals in an otherwise non-optimized system.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.