Fiber optic intruder alarm system
First Claim
Patent Images
1. Intruder detector apparatus comprising:
- intruder sensor means consisting of a length of multimode optic fiber to be positioned in an area under surveillance for intruders;
means directing a source of coherent light into said optic fiber for transmittal through said length of fiber, said transmitted coherent light emanating from the end of the fiber in a generally cone-shaped beam; and
,light detector means receiving at least a portion of the coherent light beam emanating from said fiber, the cross section of the light beam exhibiting an interference pattern of light intensity, and which interference pattern changes when said sensor means is deformed by the presence of an intruder.
1 Assignment
0 Petitions
Accused Products
Abstract
An intruder alarm for protecting the perimeter of an area utilizes a multimode optic fiber as the deformable sensing element, wherein a length of multimode optic fiber is buried in the ground of an area or perimeter to be protected. As coherent light from a laser is directed through a length of optic fiber, the output light pattern therefrom is speckled. When a deformation of the fiber occurs, even a small amount, the speckle pattern changes and is detected electronically indicating that a disturbance has taken place.
90 Citations
8 Claims
-
1. Intruder detector apparatus comprising:
-
intruder sensor means consisting of a length of multimode optic fiber to be positioned in an area under surveillance for intruders; means directing a source of coherent light into said optic fiber for transmittal through said length of fiber, said transmitted coherent light emanating from the end of the fiber in a generally cone-shaped beam; and
,light detector means receiving at least a portion of the coherent light beam emanating from said fiber, the cross section of the light beam exhibiting an interference pattern of light intensity, and which interference pattern changes when said sensor means is deformed by the presence of an intruder. - View Dependent Claims (2, 3, 4, 5)
-
-
6. An intruder alarm system comprising:
-
laser means for providing a coherent light; intruder sensor means consisting of a length of multimode optical fiber having at least a portion thereof buried in the earth of an area to be under surveillance; means directing the coherent light into one end of said optical fiber for transmittal through said length, said transmitted coherent light emanating from the other end of said fiber in a generally cone-shaped beam, the cross section of the coherent light beam exhibiting a speckle pattern of light intensity, and which speckle pattern changes when said fiber is deformed by the presence of an intruder; and
,light detector means receiving at least a portion of the coherent light beam emanating from the end of said fiber. - View Dependent Claims (7)
-
-
8. Intruder detector apparatus comprising:
-
intruder sensor means consisting of a length of multimode optic fiber to be positioned in an area under surveillance for intruders, wherein at least a portion of said length of multimode optic fiber is buried in the earth in the area under surveillance; means directing a source of coherent light into said optic fiber for transmittal through said length of fiber, said transmitted coherent light emanating from the end of the fiber in a generally cone-shaped beam; and
,light detector means receiving at least a portion of the coherent light beam emanating from said fiber, the cross section of the light beam exhibiting a speckled pattern of light intensity, and which speckled pattern changes when said sensor means is deformed by the presence of an intruder.
-
Specification