Embeddable polarimetric fiber optic sensor and method for monitoring of structures

A system for monitoring strain on a structure comprising:

• a polarization-maintaining single mode optical fiber in continuous physical contact with the structure;
• an optical light source optically coupled to the optical fiber, the optical fight source capable of supplying a light pulse into an input end of the optical fiber;
• a polarizer aligned at forty-five (45) degrees to the optical fiber's polarization axis;
• an optical interferometric device to create an optical interference from a signal emitted from an output of the optical fiber, to sense intensity chances in the interference at at least one non-predetermined point along the optical fiber corresponding to a strain on the structure transferred to the optical fiber creating a local change in birefringence of the optical fiber, and to provide an electrical signal responsive thereto;
• a signal processor to process the electrical signal to provide one or more processed output signals indicative of the location of strain at any point along the optical fiber corresponding to the at least one non-predetermined point along the optical fiber, wherein at least one said non-predetermined point does not use a discrete sensor to transfer strain to the optical fiber;
• and
• an output system that communicates the one or more output signals.

A system to detect and locate strain at any point along a structure, comprising:

• a polarization-maintaining single mode optical fiber in continuous contact with the structure, wherein a local change birefringence at a non-predetermined point along the optical fiber is created in response to a strain on the structure transferred to the optical fiber;
• a light source to supply a light to the optical fiber;
• and
• a detection unit to receive the light from the optical fiber to detect the local change in birefringence at the non-predetermined point along the optical fiber corresponding to the location of the strain on the structure, wherein at least one said non-predetermined point does not use a discrete sensor to transfer strain to the optical fiber.

A method of monitoring strain on a structure, comprising:

• physically continuously contacting the structure with a polarization-maintaining single mode optical fiber;
• directing the output of an optical light source into an input end of the optical fiber;
• directing a signal from an output end of the optical fiber into a polarizer;
• creating inference of an optical signal emitted from he polarizer by using an optical interferometric device;
• detecting intensity changes corresponding to a local change in birefringence of the optical fiber created in response to a strain on the structure transfer to the optical fiber, the local change in birefringence occurring at a non-predetermined point along the optical fiber, the strain transferred without using a discrete sensor at at least one non-predetermined point, and providing an electrical signal responsive thereto;
• and
• signal processing the electrical signal to provide one or more output signals indicative of the location of the strain on the structure.