Time-domain intensity normalization for fiber optic sensing
US4681395A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Feb 22, 1985 |
| Grant date | Jul 21, 1987 |
| Priority date | — |
| Expiry date | Feb 22, 2005 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01D5/35303
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
Disclosed is a fiber optic sensing system wherein a pulsed light source signal (12) propagates along a single optical waveguide (14) and is split into component signals (20) and (22) at a sensor unit (16). The intensity of one component signal (20) is varied by a transducer (28) through which the signal passes. The second, reference, component signal (22) passes through a delay optical fiber (30) and has its propagation delayed with respect to the other component signal (20). The delayed and undelayed component signals are then coupled and propagate along a single waveguide (34) to a receiver (36). The system is constructed so that intensity-varying factors inherent in the system, other than the sensor-induced variations, are identically shared by the two component signals. Accordingly, signal processing circuitry (38) calculates a simple ratio of the delayed and undelayed signals which yields the sensor-intensity variation independent of any other intensity-varying factors.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.