Donald L Rowe

US Patent:

44880405, Dec 11, 1984

Filed:

Nov 19, 1982

Appl. No.:

6/442984

Inventors:

Donald H. Rowe - Portola Valley CA

Assignee:

GTE Products Corporation - Stamford CT

International Classification:

G02B 514
G02B 5172

US Classification:

250227

Abstract:

A fiber optic sensor useful, for example, in intrusion detection systems for sensing seismic or pressure disturbances produced by an intruder, comprises a cable having an optical fiber core for transmitting the output of a laser, a hard preferably electrically nonconductive strand wound helically on and coextensive with the fiber, and a compliant tubular sleeve over the fiber and strand. The coils of the strand are axially spaced apart and circumferentially engage the fiber. The sleeve fits snugly over the strand and fiber and transmits through the strand coils to the fiber forces resulting from disturbances to be detected, subjecting the fiber to bending stresses. With cable connected at one end to the laser output, the polarization of light transmitted by the fiber is changed by the induced stresses and is detected at the other end of the cable to indicate the occurrence of the disturbance.