Abstract

The propagation characteristics of an optical fiber are determined solely by its refractive-index profile. Conventional characteristics of an optical fiber are determined solely by its refractive-index profile. Conventional measurement methods, using refracted-near-field techniques, are both limited in resolution and prone to refractive-index calibration errors. To avoid these pitfalls, we introduce a fast, accurate method for characterizing the fine details of single-mode fiber core profiles, such as central dips and dopant diffusion which can influence modal propagation. This method is valid for matched- and depressed-cladding fibers. It used modal interferometry^1,2 to determine group velocity equalization wavelengths for several mode pairs.

© 1991 Optical Society of America