Shape Sensing Using a Multi-Core Optical Fiber Having an Arbitrary Initial Shape in the Presence of Extrinsic Forces

NASA’s Langley Research Center has demonstrated a patent-pending method and apparatus for determining the position, in three dimensions, of any point on an optical fiber. The new method uses low-reflectance Fiber Bragg Grating (FBG) strain sensors in a multicore fiber to determine how any point along that fiber is positioned in space. The characteristics of optical fibers and the FBGs vary with curvature, and by sensing the relative change of FBGs in each of three or more fiber cores, the three-dimensional change in position can be determined. By using this method in monitoring applications where optical fibers can be deployed — such as in structures, medical devices, or robotics — precise deflection, end position, and location can be determined in near real time. This innovative position detection method offers 10 times greater positional accuracy than comparable optical techniques.