Fiber laser pressure sensor
US6630658B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Nov 20, 2000 |
| Grant date | Oct 7, 2003 |
| Priority date | — |
| Expiry date | Nov 20, 2020 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG02B6/105
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
The invention relates to a frequency-coded fiber laser pressure sensor (1) which is especially suitable for measuring isotropic pressures in oil wells. The sensor principle provided for in the invention is based on the fact that in a fiber laser (2) doped with Er3+ a monomode or bimodal sensor fiber (5, 5a, 5b) is positioned whose pressure-related birefraction results in a frequency shift and beat frequencies between the orthogonal linear polarisation modes x, y or the spatial modes LP01 and LP11straight line. The beat frequencies are easily measured using a frequency counter (19). Temperature-related variations in birefraction are compensated in a differential arrangement of two sensor fiber segments (5a, 5b). Fiber-integrated Bragg gratings (4a, 4b) with low bandwidths (0.2 nm) are especially suitable as laser end reflectors. The pressure sensor (1) is characterized by a large measurement range (100 Mpa) and a high triggering capacity , (kPa), is readily multiplexed and can be housed in a very compact, light-weight and robust pressure-resistant housing (25).
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.