Quantitative phase imaging of fiber Bragg gratings

The refractive index (RI) characterization of fiber Bragg gratings (FBGs) is crucial in monitoring and validating these fabricated structures. Quantitative phase imaging (QPI) is a uniquely promising candidate to accomplish refractive index characterization with the simultaneous benefits of noninvasive technique, sub-micron resolution, and quantitative 3D recovery of refractive index. Approaches are presented to overcome challenges that have previously acted as major obstacles in this field of research. A form of tomographic deconvolution phase microscopy (TDPM) is used to experimentally demonstrate the characterization abilities QPI can provide for various classes of FBGs.M.S