The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jan. 07, 1986
Filed:
Apr. 05, 1983
Bernard Desormiere, Paris, FR;
Thomson CSF, Paris, FR;
Abstract
An optical magnetometer for measuring the component h of a magnetic field in a direction x by the Faraday effect. A semiconductor laser produces two laser beams which are directed from opposite faces of the laser in opposite directions along two fiber optic cables. The opposite beams of light enter a magneto-optical medium and then continue via the opposite fiber optic cable to return to the laser where the two light beams are recoupled. An alternating magnetic field at frequency f and a compensation field are applied to the magneto-optical medium in a direction parallel to the direction x to produce the Faraday effect. The laser intensity of the recoupled light beams is proportional to the magnetic field to be measured. A photodetector samples portions of the recoupled light beam and provides a current i.sub.d which is proportional to the recoupled beam intensity. The current i.sub.d is filtered at frequencies f, for compensating the field h to be measured, and 2f. The magneto-optical medium used is preferably formed by a substituted YIG ferrimagnetic layer, grown by epitaxy on a non-magnetic garnet.