Gradual-Time Solution Doping for the Fabrication of Longitudinally Varying Optical Fibres

Standard MCVD process and solution doping are commonly used for processing rare-earth doped optical fibers. Since the 1970s, this technique is mainly employed to fabricate homogeneous preforms in the longitudinal direction. A variant is proposed here, by using two doping solutions and by applying a gradual time doping. To demonstrate the validity of this approach, three preforms were prepared with longitudinal gradient of La, Ce, and Al. Preforms were characterized by refractive index profile measurements and concentrations in optical fibers were characterized by EPMA. These results will allow to perform rapid material development in optical-fiber domain. This process is also expected to offer a new way to prepare optical fibers with varying longitudinal characteristics.