| 摘要 |
PURPOSE:To manufacture a base material for an optical fiber having the desired refractive index distribution when a base material for an optical fiber is manufactured by melting and depositing glass contg. a dopant on the growing face of a sintered glass body, by detecting the refractive index distribution of the growing face under irradiated ultraviolet rays to control the manufacturing conditions. CONSTITUTION:While rotating a sintered glass body 2, a starting material 10 for glass, a starting material 11 for a dopant for regulating the refractive index, gaseous oxygen 12 and gaseous hydrogen 13 are fed to the lower growing face 5 of the body 2 through a burner 1. Fine glass and dopant particles are synthesized by oxidation and hydrolysis with a hot hydrogen flame 14 in the burner 1, and they are deposited on the growing face 5 of the body 2. The face 5 is then scanned with ultraviolet rays 7 through a polarizer 4, the generated fluorescence is recorded with a camera 6, and the refractive index distribution of the face 5 is obtd. by operation with a signal processing system 20. The signal is compared to the desired refractive index distribution signal from a refractive index distribution signal generator 21 with an operator 22, the result is fed back to a controller 30, and the operation of the burner 1 is controlled so as to provide the desired refractive index distribution. |
