Optical fiber and process of producing the same

摘要

A process for the production of an optical fiber a core which is elliptical in cross-section at one end and circular at the other end and which has little transmission loss and less of a reduction in the difference in indexes of refraction between the core and cladding, which consists of heating an optical fiber (1) having a core (c) having a uniform cross-sectional area in the longitudinal direction and a cladding (2) formed with at least one through hole (4A) along the longitudinal direction of the core while successively changing the heating temperature along the longitudinal direction of the optical fiber so as to continuously change the shape of the through hole, continuously change the cross-sectional shape of the core along the longitudinal direction of the optical fiber, and thereby make the cross-sectional shape of the core at one end of the optical fiber and the cross-sectional shape of the core at the other end different.