Non-zero dispersion shifted optical fibre

摘要

A single mode optical waveguide fibre is disclosed which preferably is formed to exhibit low but non-zero dispersion at a wavelength lambda in the order of 1550 nm. The fibre has a light guiding region that includes a central core region (11), a core-surrounding region (14) and at least three angularly separated side core regions (13) that are disposed radially outwardly from the central core region. The central core region (11) has an average refractive region n0, the surrounding region (14) has an average refractive index n1n0, and each of the angularly separated regions (13) have an average refractive index n2n1.