Patent ID: 6817213
Filing Date: 2004-11-16
Classification: C03B,C03C

Abstract:
A method of fabricating an optical fiber comprising:depositing a first cladding having an outer diameter D so as to surround a core having an outer diameter d to make a porous core rod of D/d&gE;4.0, by using a vapor-phase axial deposition method; dehydrating the porous core rod to reduce an OH group concentration in the porous core rod to 0.8 ppb or less by weight; vitrifying the porous core rod after the dehydrating the porous core rod step to make a core rod; stretching the core rod; depositing a second porous cladding around the core rod after the stretching step by using a vapor-phase deposition method; dehydrating the second porous cladding to reduce an OH group concentration to 50 ppm or less by weight; vitrifying the second porous cladding after the dehydrating the second porous cladding step to make an optical fiber preform; and drawing the optical fiber preform to make an optical fiber, wherein the optical fiber formed via said drawing step has a transmission loss at a wavelength of 1.38 &mgr;m less than a transmission loss at a wavelength of 1.31 &mgr;m both before and after exposure to a 1% H2 atmosphere at room temperature for 4 days.