Patent ID: 7658086

Claim:
A drawing method for a silica-based bare optical fiber, the method comprising the steps of: melting a silica-based optical fiber preform using a heating device, drawing a heated and molten portion of the optical fiber preform to obtain a bare optical fiber; and cooling the bare optical fiber, wherein during the drawing step, in order to suppress a diffusion of hydrogen generated from an OH group due to thermal dissociation of the OH group, the temperature of the heated and molten portion of the optical fiber preform cannot exceed 1800° C. for longer than a time period T (min) defined by the relational expression T=−0.01X+12, where X (wtppm) is the OH group concentration in a cladding layer of the optical fiber preform, and the OH group concentration in the cladding layer is in the range of 100 to 500 wtppm.