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:
May. 07, 2002
Filed:
Oct. 25, 2000
Samuel N. Fersht, Studio City, CA (US);
David B. Hall, La Crescenta, CA (US);
Carl Bathelt, Simi Valley, CA (US);
Northrop Grumman Corporation, Los Angeles, CA (US);
Abstract
A fiber optic seismic sensor includes a central support assembly formed of a metal such as aluminum. A support plate has an inner portion retained within the central support assembly and an outer portion that extends beyond the central support assembly. A pair of hollow cylindrical substrates are mounted in axial alignment on opposite sides of the outer portion of the support plate with the central support assembly extending through the centers of the substrates. The central support assembly comprises a first central support member having a cavity in one end, and a second central support member having a projection extending therefrom and arranged to be received within the cavity in the first central support member. The support plate includes a passage arranged to receive the projection such that the inner portion of the support plate is retained between the first and second central support members. A first spiral-wound optical fiber coil is formed on an outer end of the first substrate, and a second spiral-wound optical fiber coil is formed on an outer end of the second substrate. An interferometer includes the first spiral-wound optical fiber coil in a first leg and the second spiral-wound optical fiber coil in a second leg. Acceleration along an axis perpendicular to the planes of the optical fiber coils causes a deflection in the support plate, which changes the pathlength difference between the legs of the interferometer.