Method and apparatus for optically measuring electric and magnetic quantities having an optical sensing head exhibiting the Pockel's and Faraday effects
US4933629A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jul 7, 1989 |
| Grant date | Jun 12, 1990 |
| Priority date | — |
| Expiry date | Jul 7, 2009 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01R15/24
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A method and an apparatus for measuring the strength of an AC electric field or an equivalent voltage, or the strength of an AC magnetic field or an equivalent current, based on a light beam which is transmitted through and thus modulated by an optical sensing head due to the Pockel's and Faraday effects, while the sensing head is exposed to the AC electric and magnetic fields. The sensing head includes an optical material which exhibits the Pockel's effect and an optical material which exhibits the Faraday effect, or includes an optical material which exhibits both the Pockel's and Faraday effects. The modulated beam is applied to a light-sensitive element, which produces an electric output signal. A first and a second component of the electric output signal are retrieved by respective detectors. The first component has a same frequency as that of the electric or magnetic field, while said second component has a frequency which is two times that of said electric or magnetic field. The electric field strength or the voltage, and the magnetic field strength or the current are determined by one and the other of the first and second components, respectively.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.