Patent ID: 8746076

Claim:
A method of determining the shape of a multi-core optical fiber, the method comprising: initializing a controller, including: positioning the multi-core fiber in an arbitrary initial shape; determining an initial curvature vector of the fiber that describes the arbitrary initial shape; and initializing strain measurements using the controller; and determining the shape of the fiber, including: positioning the fiber in a desired shape to be measured; measuring strain over a length of the fiber using a plurality of strain sensors while the cable is held in the shape to be measured, wherein the strain sensors are distributed along a length of each of the cores; defining a three-coordinate p-vector for each of the cores as a function of the distance of each respective core from a center point of the fiber and a bending angle of each respective core with respect to a local axis of the fiber, wherein the coordinates of the p-vector define a plane; calculating, via the controller, an applied strain value of the fiber using the p-vector and the measured strain; calculating strain due to bending as a function of the measured strain and the applied strain value; defining an apparent local curvature vector for each core of the fiber as a function of the calculated strain due to bending; calculating curvature and bend direction of the fiber using the apparent local curvature vector and the initial curvature vector; and determining the shape to be measured via the controller using the calculated curvature and bend direction.