| 摘要 |
PURPOSE:To obtain the titled parent material causing no deformation by softening nor deterioration of characteristics for a long period and having superior controllability for refractive index by feeding gaseous CO together with feed gas and gaseous O2 into a glass pipe heated externally and burning the gases. CONSTITUTION:A glass pipe 1 set freely detachably to a glass lathe being supported freely rotatably is heated by burning H2 with O2 with a burner 2 provided freely movably back and fourth in the longitudinal direction of the pipe, and gaseous CO is fed together with feed gas (e.g. SiCl4, GeCl4) and gaseous O2 to the rotating pipe 1 to cause combustion, thus, soot-like fine glass particles are formed by the reaction and melted in accordance with the movement of CVD zone 4 accompanying the movement of the above described burner to form transparent glass. Thus, an SiO2-GeO2 glass layer 3 is deposited to form a specified thickness layer on the inside periphery of the pipe 1. Then, the pipe is collapsed and then the dia. is reduced to produce the titled parent material. |
