Method for Predicting Rayleigh Scattering Loss of Silica-Based Optical Fibers

In order to fabricate low-loss silica-based fibers cost-effectively, we propose a method that can be utilized to predict their Rayleigh scattering loss before they are drawn. The method is based on the relationship between their fictive temperature and drawing conditions such as drawing speed, length, and temperature distribution in the furnace. First, we constructed a theoretical model that describes the effects of fictive temperature, dopant concentration, and optical power distribution in the fiber cross section on the Rayleigh scattering loss. We applied the model to a GeO₂-doped silica-core single-mode fiber and confirmed that the experimental and calculated Rayleigh scattering values were in good agreement within a relative error of 3%. Using the model as a basis, we demonstrate that the Rayleigh scattering loss of silica-based fibers can be minimized by optimizing their cooling conditions in accordance with their drawing speed.