Non-Destructive Three-Dimensional Optical Imaging of a Fiber Bragg Grating

Here, we demonstrate a non-destructive quantitative phase imaging method, in conjunction with tomographic reconstruction techniques, to reconstruct the three- dimensional refractive index distribution of a fiber Bragg grating. In addition to being able to extract the fundamental period of the grating, we are able to reconstruct the refractive index profile of the fiber core and index variations associated with the grating.