Natural fiber span reflectometer providing a virtual phase signal sensing array capability
US7271884B2 · kind B2 · utility
Assignee
Inventor
Key dates
| Filing date | Feb 7, 2005 |
| Grant date | Sep 18, 2007 |
| Priority date | — |
| Expiry date | Dec 1, 2025 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01M11/3172
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A CW lightwave modulated by a continuously reiterated psuedorandom code sequence is launched into an end of a span of ordinary optical fiber cable. Portions of the launched lightwave back propagate to the launch end from a continuum of locations along the span because of innate fiber properties including Rayleigh scattering. This is picked off the launch end and heterodyned producing a r.f. beat signal. The r.f. beat signal is processed by a plurality (which can be thousands) of correlator type pseudonoise code sequence demodulation and phase demodulator units, operated in different time delay relationships to the timing base of the reiterated modulation sequences. These units provide outputs representative of phase variations in respective unique spectral components in the r.f. beat signal caused by acoustic, or other forms of, signals incident to virtual sensors at fiber positions corresponding to the various time delay relationships.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.