James W. Fleming

Dispersion in GeO 2 –SiO 2 glasses

Germania glass was prepared from high purity GeO2 powder. Refractive-index dispersion was used to calculate material dispersion and to provide a model for representing the dispersion of GeO2–SiO2 glasses. The wavelength of zero material dispersion is found to be in agreement with theoretical calculations. Modal propagation is modeled for a GeO2 core–silica clad fiber. Results support compositional dependence of profile dispersion in GeO2–SiO2 fibers.

Refractive index dispersion and related properties in fluorine doped silica

Refractive index dispersion has been determined for fluorine doped fused silica containing 1 and 2% fluorine. Addition of fluorine is found to reduce the refractive index and material dispersion. Fibers modeled for minimization of modal dispersion having fused silica cores and fluorine doped silica cladding show a strong composition dependence of the optimum refractive index profile. Comparison of results with those in the literature based on N.A. vs λ measurements reveal minor discrepancies probably due to the drawing process.

Dispersion in step-index silicone-clad fibers

Optical properties of materials making up multimode step-index fibers with inorganic glass cores and silicone cladding have been examined using bulk sample measurement techniques. Mode dispersion and numerical aperture for the wavelength range 0.4-1.4 microm for two fibers are reported.