Abstract

Fluorine doping has been useful in the reduction of transmission loss in VAD single-mode fibers. A high yield of low-loss fiber under 0.20 dB/km at 1.55 μm was achieved in fully fluorine-doped single-mode fibers with a nonshifted design in which fluorine is doped in cladding and is slightly added to the pure silica core.¹ The similar approach has been successfully applied to dispersion-shifted fibers with dual shape refractive-index profiles with encouraging results for reducing the transmission loss to 0.20 dB/km.² Refractive-index profiles and doping of fluorine for these fibers are illustrated in Fig. 1.

© 1988 Optical Society of America