To study material dispersion effects on transmission characteristics in optical fibers, material dispersion properties in GeO2-P2O5-doped silica optical fibers were determined as a function of GeO2 doping concentration. The material dispersion properties were evaluated from pulse delay measurement with nanosecond pulses in a 0.60-1.65 µm spectral region generated by a nanosecond optical pulse radiator. From the measured delay, refractive index of core glass, material group index, material dispersion, zero-material-dispersion wavelength and zero-dispersion wavelength in a single mode fiber have been determined as a function of GeO2 doping concentration in the range 4.1 to 19.2 mol %. By extrapolating present data in GeO2-P2O5-SiO2 ternaries, material dispersion properties in fused GeO2 glass have been predicted. The zero-material-dispersion wavelength in fused GeO2 glass can be estimated to be 1.68 0.03 µm.

This letter reports in detail on the temperature-dependent signal gain characteristics of Er3+-doped optical fiber amplifiers at signal wavelengths of 1.536µm and 1.552µm. The amplifiers were pumped at 0.825µm in a temperature range of 40 to 200. The signal gain for optimum length at both wavelengths stops increasing and begins to decrease at about 80. In the temperature region below 80, both signal gains increase with fiber temperature for fibers of optimum length or less. A temperature independent length aroud the optimum length is observed from 80 to 200 for both signal wavelengths. Theoretically, the temperature dependence of the signal gain characteristics rerults from the changes in fluorescence, absorption, GSA and ESA cross sections.