| 摘要 |
PURPOSE:To prevent roughness on the surface of a piled layer caused by etching and to obtain the titled parent material of low loss, by omitting a process such as anisotropic etching of the piled layer on the inner face of a quartz tube. CONSTITUTION:A gas-phase chloride raw material, O2 and an operating gas are made to flow from a raw material feed pipe 6 without rotating a quartz tube 1 kept in a given pressure state, a plasma pole 8 excited from a microwave oscillator 10 through a waveguide 9 by a microwave cavity resonator 7 is introduced into the quartz tube in such a way that the plasma pole rectangularly crosses the axis of the quartz tube 1 and the resonator 7 is reciprocated along the axial direction of the quartz tube 1 to pile a glass layer 2' to constitute a stress imparting part. Then the quartz tube 1 is rotated by a rotary connector 5, a gas-phase chloride raw material, O2 and an operating gas are fed to the quartz tube, simultaneously the resonator 7 is reciprocated in the axial direction of the quartz tube 1 to pile a synthetic clad layer 3 and a synthetic core layer 4 is piled in the same manner as the above-mentioned manner. Then oxyhydrogen flame is reciprocated from the outside in the revolution direction while rotating the quartz tube 1, the layers are heated and collapsed. |
