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:
Jul. 15, 1986
Filed:
May. 15, 1984
Kee P Koo, Alexandria, VA (US);
Anthony Dandridge, Alexandria, VA (US);
Alan B Tveten, Fort Washington, MD (US);
George H Sigel, Jr, Great Falls, VA (US);
The United States of America as represented by the Secretary of the Navy, Washington, DC (US);
Abstract
A fiber optic magnetometer for detecting DC magnetic fields includes a first optical fiber having a magnetostrictive jacket thereon which defines a sensing arm, and a second fiber defining a reference arm. An AC magnetic field of frequency .omega..sub.o and constant amplitude is imposed on the magnetostrictive jacket so as to cause a time varying optical path length change, having an .omega..sub.o component, in the sensing arm fiber. This induces a corresponding time varying phase shift, also having an .omega..sub.o component, in light transmitted through the sensing arm fiber which is detected by a phase detector. The phase detector produces a signal proportional to the phase shift, this signal being passed to a lock-in amplifier set to amplify at .omega..sub.o. The lock-in amplifier produces an output signal proportional to the amplitude of the .omega..sub.o component, wherein this amplitude is proportional to any DC magnetic fields to which the device is exposed.