| 摘要 |
PROBLEM TO BE SOLVED: To provide an optical fiber preform which can reduce the manufacturing cost of the optical fiber by fixing the ratio in the longitudinal direction between the outer diameter of the clad part and the outer diameter of the core part. SOLUTION: First of all, a pre-production glass rod and a pre-production glass tube are prepared (S201). A pre-production optical fiber preform is made of them (S202). Then, the refraction index distribution is measured at several positions along the longitudinal direction of the pre-production optical fiber preform (S203). Based on the results of the measurement, the required distribution of wall thickness which a glass tube for manufacturing the optical fiber preform should have is calculated (S204). Thereafter, a glass tube for manufacturing the optical fiber preform is manufactured by grinding the periphery of a glass tube which has the almost similar shape and quality to the pre- production glass tube (S205). Then, the optical fiber preform is manufactured by heating and integrating the glass tube for manufacturing the optical fiber preform and a glass rod which has the almost similar shape and quality to the pre-production glass rod (S206). |
