Fiber optic geophone
US6161433A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Oct 15, 1999 |
| Grant date | Dec 19, 2000 |
| Priority date | — |
| Expiry date | Oct 15, 2019 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01P15/093
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A geophone includes an optical element capable of changing its refractive index and path length in response to acceleration of the geophone. The sensor component comprises a mass mounted on a fulcrum for rotational movement against the force of a biasing member. An optical fiber is stretched between the casing of the sensor and an extension of the mass, such that rotational movement of the mass about the fulcrum varies the tension in the fiber. Varying the tension in the fiber varies the optical path length and index of refraction of the fiber, and these variations may be detected as a seismic signal. A first set of magnets dampens the vibratory movement of the mass, and a second set of magnets reduces the frequency of the movement of the mass.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.