Segmented cladding fiber fabricated in silica-based glass

We report fabrication of a segmented cladding fiber (SCF) in silica-based glass. An SCF with a uniform core of pure silica and cladding of periodically arranged pure silica and fluorine-doped silica in an angular direction has been fabricated by using the stack-and-draw technique. The fabricated fiber has been characterized by capturing its near-field intensity pattern at 633 nm wavelength. The number of modes has been estimated from the captured near-field intensity pattern by using neural network analysis. A four-segment SCF of 30-μm core diameter and 0.43% relative index differences between the high- and low-index segments shows few-mode operation by filtering out higher-order modes of an otherwise highly multimode fiber.