Apparatus and method for processing optical signals from two delay coils to increase the dynamic range of a sagnac-based fiber optic sensor array
US6667935B2 · kind B2 · utility
Assignee
Inventor
Key dates
| Filing date | Aug 2, 2002 |
| Grant date | Dec 23, 2003 |
| Priority date | — |
| Expiry date | Aug 2, 2022 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01H9/004
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A folded Sagnac fiber optic sensor array uses a common delay path to reduce distributed pickup in downlead fibers. The sensor array is used to detect perturbations (e.g., acoustic waves in water). By basing the folded Sagnac sensor array on operating principles similar to the Sagnac interferometer the sensor array has a stable bias point, has reduced phase noise, and allows a broadband signal source to be used rather than requiring a more expensive narrowline laser. A large number of sensors can be multiplexed into the architecture of the sensor array. In one particularly preferred embodiment, the sensor array is configured with couplers and amplifiers selected to direct substantially equal portions of an input light signal to each sensor in the array. In another particularly preferred embodiment, first and second delay paths are provided for light at first and second wavelengths to increase the dynamic range of the sensors.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.