B.S.T.J. Briefs: Fabrication and Properties of Single-Mode Optical Fiber Exhibiting Low Dispersion, Low Loss, and Tight Mode ConfinementSimultaneously

In a previous publication, Lazay et al.1 reported a single-mode fiber design with a new refractive index profile that allows the wavelength of zero total dispersion to be positioned in the vicinity of 1.31 /mi, while simultaneously providing low loss and tight mode confinement. This report will describe the fabrication and properties of fibers of this new design. The design uses a heavily fluorine-doped phosphosilicate cladding and a germania-doped silica core. The core and cladding compositions were chosen to provide a reduced material dispersion that cancels the waveguide dispersion near 1.3 /mi. At the same time, the total core-toclad index difference was chosen to give a delta of 0.5 percent, sufficient to produce a small modal size and excellent resistance to curvatureinduced losses. We anticipate that the losses ultimately achievable with this new design will be lower than those of step-index Ge02-Si02 core fibers of the same core diameter, largely because of the reduced contribution from Ge scattering. Ainslie et al.2 have pointed out the 262