REFRACTIVE INDEX DISTRIBUTION MEASUREMENT METHOD AND REFRACTIVE INDEX MEASUREMENT INSTRUMENT FOR OPTICAL FIBER BASE MATERIAL

摘要

PROBLEM TO BE SOLVED: To provide a refractive index distribution measurement method and a refractive index distribution measurement instrument for an optical fiber base material, which easily measure a refractive index distribution of an optical fiber base material having striae, with high accuracy.;SOLUTION: A refractive index distribution measurement instrument 10 for an optical fiber base material 20 includes: first and second lasers 11 and 12 which emit two monochromatic beams having different wavelengths λ₁ and λ₂; a CCD array 21 being a photodetector which measures a light intensity distribution of transmitted light transmitted through the optical fiber base material 20; and a calculation device 22 which obtains a transmission deflection angle Φ from the light intensity distribution detected by the photodetector to calculate a refractive index distribution n(r). Light intensity distributions of transmitted light at wavelengths λ₁ and λ₂ which is transmitted through one cross-section of the optical fiber base material 20 are measured, and the light intensity distributions of two monochromatic beams are compared with each other to measure the transmission deflection angle Φ, and the refractive index distribution n(r) of the optical fiber base material 20 is obtained from a group of transmission deflection angles Φ.;COPYRIGHT: (C)2013,JPO&INPIT