Nanoscale Investigations of Optical Fiber by Using Scattering Scanning Near-Field Optical Microscopy

Scattering Scanning Near-field Optical Microscopy (s-SNOM) is proposed as a powerful tool for quantitative analysis of cross-sectional area of optical fibers. The s-SNOM images are processed pixel-by-pixel in order to map the refractive index of the optical fibers’ cross-sectional surface. s-SNOM imaging technique is widely known for its capability to reach nanoscale resolution, therefore the obtained maps of refractive index based on s-SNOM data are as well characterized by nanoscale resolution. Combined with Atomic Force Microscopy (AFM) images simultaneously acquired with s-SNOM, this technique proves to be a powerful tool not only for characterization of refractive index profile of optical fibers, but also for quality check of optical fibers (or other types of optical waveguides) at nanoscale. Particularly, in this study we prove the capability of s-SNOM to map the refractive index of cross-sectional area of a Panda-style polarization-maintaining single mode optical fiber.