Dopant concentration difference measuring method and dopant concentration difference measuring apparatus

摘要

PROBLEM TO BE SOLVED: To measure the difference in the concentrations of aluminum and phosphorus added to a core part of the base material for an optical fiber.SOLUTION: The method for measuring the difference in the concentration of a dopant includes the step of irradiating a core part 11 with a measurement light L in a wavelength band that a rare-earth element added to the core part 11 of the base material 1 for an optical fiber absorbs (step S1); acquiring the absorption spectrum of the light absorbed to the core part 11 on the basis of the spectrum of the measurement light L passing through the core part 11 (step S2); and estimating the difference in the concentration between aluminum and phosphorus added to the core part 11 on the basis of the absorption spectrum (step S3).SELECTED DRAWING: Figure 3