Fabrication of Yb2O3–Al2O3–P2O5–SiO2 Optical Fibers with a Perfect Step-Index Profile by the MCVD Process

An all-vapor phase MCVD process has been proposed for the fabrication of fiber preforms with a Yb 2 O 3 –Al 2 O 3 –P 2 O 5 –SiO 2 multicomponent glass core. We have investigated the tubular preform collapse into a rod and demonstrated approaches capable of preventing P 2 O 5 losses in the central part of the core during the collapse process. Preforms with a flat, perfect step-index profile have been fabricated.