PURPOSE: To provide the method and apparatus for producing the plastic optical fiber preform of a GI type.
CONSTITUTION: A polymer A (refractive index: Na) and a compd. B (refractive index: Nb) having the refractive index different from the refractive index of this polymer A are used and ≥2 kinds of raw material vapors varying in their compounding ratios are formed in the process for production of the plastic optical fiber preform by depositing gaseous materials on the bottom end a supporting rod 11 rotating around its axis by a VAD(Vapor-phase Axial Deposition) method and gradually pulling up this supporting rod 11. The raw material vapor having the high refractive index is blown near to the central part of the supporting rod 11 via the nozzle 12a and the raw material vapor of the low refractive index is blown thereto via a nozzle 12b in such a manner that the blowing range varies from the central part toward the outer peripheral part. The refractive index distribution in which the refractive index is successively lowered from the center to the outside diametral direction of the optical fiber preform is thus formed.
HOSOYA TOSHIFUMI
KOBAYASHI TAKEHITO
MATSUDA HIROO
