Influence of temperature on the backscattering signal in large-aperture fiber waveguides

An investigation was made of the influence of heating in the temperature range 20–900 °C on the losses and backscattering signal observed in quartz fiber waveguides with SiO₂–GeO₂–P₂O₅ and SiO₂–GeO₂ cores. The temperature sensitivity of the backscattering signal was 0.33 X 10 ^{– 3} dB/°C in the range 20–750 °C and 0.5 X 10 ^{– 3} dB/°C in the range 20–850 °C, respectively. In the case of the fibers with the SiO₂–GeO₂–P₂O₅ core the backscattering signal increased irreversibly because of heating by an amount which depended on the maximum temperature reached in the experiments.