Fabrication method and fabrication apparatus for porous glass base material for optical fiber
AssigneeShin-Etsu Chemical Co., Ltd.
InventorTetsuya Otosaka
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Abstract
According to a fabrication method for fabricating a porous glass base material for optical fiber, the orientation of a clad forming burner used to form the outermost layer of a clad-corresponding portion is changed further upward while glass fine particles are deposited during the period between a first timing and a second timing. At the first timing, the outer diameter of the porous glass base material for optical fiber has not reached a target outer diameter. The second timing is later than the first timing, and either a timing at which the outer diameter of the porous glass base material for optical fiber reaches the target outer diameter for the first time, or a timing prior to this timing.
Claims7
A fabrication apparatus for fabricating a porous glass base material for optical fiber, comprising:
- a reaction vessel configured to house therein a hanging seed rod;
- a core forming burner configured to deposit glass fine particles onto the seed rod to form a core-corresponding portion that is to be formed into a core of optical fiber;
- two clad forming burners including a surface-side clad forming burner and a core-side clad forming burner configured to deposit glass fine particles that are to be formed into a clad of the optical fiber, onto the core-corresponding portion to form at least an outermost layer of a clad-corresponding portion that is to be formed into the clad of the optical fiber, the core-side clad forming burner being positioned in a vertical direction between the core forming burner and the surface-side clad forming burner;
- a driver configured to change an orientation of the surface-side clad forming burner;
- and
- a controller configured to control the driver to, while the glass fine particles are deposited by the surface-side clad forming burner, change a gradient of the surface-side clad forming burner used to form at least the outermost layer of the clad-corresponding portion from a negative angle to a positive angle relative to a horizontal plane as formation of the porous glass base material proceeds.
Dependencies are inferred from the claim text.