Optical fibre magnetic gradient detector
US4665363A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Feb 20, 1986 |
| Grant date | May 12, 1987 |
| Priority date | — |
| Expiry date | Feb 20, 2006 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01R33/0327
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
Two portions (B,C) of one arm of an optical fibre Mach-Zehnder interferometer are magnetically sensitized and each has applied thereto an a.c. bias fields at a respective different frequency (w.sub.1, w.sub.2). One portion (A) of the other arm of the interferometer is magnetically sensitized and has two a.c. bias fields applied thereto, each at one of the different frequencies (w.sub.1,w.sub.2). The fields for portion A and C are aligned with a first direction (x) whereas those for A and B are parallel, A and B being separated in a second direction (y). The detected output of the interferometer at frequency w.sub.1 is related to the magnetic gradient in the y direction, whereas the detected output at frequency w.sub.2 is related to the magnetic gradient in the x direction. Thus using two bias frequencies allows one interferometer to be used to detect two gradients (FIG. 8).
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.