MANUFACTURE OF SINGLE-MODE LIGHTGUIDE FIBER AND OPTICAL-FIBER CORE PREFORM

摘要

PURPOSE: To provide a single mode optical fiber fitted to the transmission of solitons. CONSTITUTION: The fiber has a refraction factor distribution changing along the length of the fiber so that fiber dispersion which monotonously reduces from one end part to the other end part along the fiber. The fiber has a maximum refraction factor n1 and a radius (a) and is provided with the core surrounded by a clad material having the refraction factor n2 which is lower than n1 . The fiber core has a center area extending to the axis of the longitudinal direction of the fiber and an outer area, and the inner and outer areas are separated by the area of the subsided refraction factor. The inner radius a1 of the area with the subsided refraction factor is larger than zero and the maximum radius a0 of the area with the subsided refraction factor is smaller than (a). A fiber preform is generated by depositing the layer of glass particles on a long mandrel. The composition of glass particles is changed by the position of the longitudinal direction along the preform when the layer is deposited for several times.