Method for Manufacturing a Glass Preform for Optical Fibers
First Claim
1. A method for manufacturing a fluorine-doped glass preform for optical fibers, the method comprising:
- exposing a soot preform to an atmosphere containing a fluorine-containing gas in a first elongated chamber of a first furnace, the first elongated chamber having a single isothermal hot zone kept at a doping temperature of from 800°
C. to 1200°
C. to obtain a fluorine-doped soot preform;
dehydrating the fluorine-doped soot preform by exposing it to an atmosphere containing a chlorine-containing gas and being substantially devoid of fluorine in a second elongated chamber of a second furnace, the second elongated chamber having an upper hot zone at a dehydration temperature of from 1000°
C. to 1350°
C. and a lower hot zone at a consolidation temperature of from 1500°
C. to 1650°
C., wherein dehydration takes place in the upper hot zone of the second furnace; and
consolidating the fluorine-doped soot preform by moving it down into the lower hot zone of the second furnace so as to form a fluorine-doped glass preform.
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Accused Products
Abstract
Methods for manufacturing fluorine-doped glass preforms for optical fibers are disclosed. An exemplary method includes exposing a soot preform to an atmosphere containing a fluorine-containing gas in a first elongated chamber of a first furnace. The first elongated chamber typically has a single isothermal hot zone, which may be maintained at a doping temperature of about 800° C. to 1200° C., to obtain a fluorine-doped soot preform. The exemplary method further includes dehydrating the fluorine-doped soot preform by exposing it to an atmosphere containing a chlorine-containing gas in a second elongated chamber of a second furnace. The second elongated chamber typically has an upper hot zone, which may be maintained at a dehydration temperature of about 1000° C. to 1350° C., and a lower hot zone, which may be maintained at a consolidation temperature of about 1500° C. to 1650° C. Dehydration of the fluorine-doped soot preform typically occurs in the upper hot zone of the second furnace. The exemplary method further includes consolidating the fluorine-doped soot preform within the lower hot zone of the second furnace to form a fluorine-doped glass preform.
1 Citation
20 Claims
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1. A method for manufacturing a fluorine-doped glass preform for optical fibers, the method comprising:
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exposing a soot preform to an atmosphere containing a fluorine-containing gas in a first elongated chamber of a first furnace, the first elongated chamber having a single isothermal hot zone kept at a doping temperature of from 800°
C. to 1200°
C. to obtain a fluorine-doped soot preform;dehydrating the fluorine-doped soot preform by exposing it to an atmosphere containing a chlorine-containing gas and being substantially devoid of fluorine in a second elongated chamber of a second furnace, the second elongated chamber having an upper hot zone at a dehydration temperature of from 1000°
C. to 1350°
C. and a lower hot zone at a consolidation temperature of from 1500°
C. to 1650°
C., wherein dehydration takes place in the upper hot zone of the second furnace; andconsolidating the fluorine-doped soot preform by moving it down into the lower hot zone of the second furnace so as to form a fluorine-doped glass preform. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A method for manufacturing a fluorine-doped glass preform for optical fibers, the method comprising:
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exposing a soot preform to an atmosphere containing a fluorine-containing gas in a first elongated chamber of a first furnace, the first elongated chamber having an isothermal hot zone maintained at a doping temperature between 800°
C. and 1200°
C. to obtain a fluorine-doped soot preform;dehydrating the fluorine-doped soot preform by exposing it to an atmosphere containing a chlorine-containing gas in a second elongated chamber of a second furnace, the second elongated chamber having a dehydration hot zone maintained at a dehydration temperature and a consolidation hot zone maintained at a consolidation temperature, wherein dehydration takes place in the dehydration hot zone of the second furnace, wherein the consolidation temperature of the consolidation hot zone is greater than the dehydration temperature of the dehydration hot zone; and consolidating the fluorine-doped soot preform by positioning it within the consolidation hot zone of the second furnace so as to form a fluorine-doped glass preform. - View Dependent Claims (12, 13, 14, 15, 16, 17, 18)
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19. A method for manufacturing a fluorine-doped glass preform for optical fibers, the method comprising:
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(i) exposing a soot preform to an atmosphere containing a fluorine-containing gas and being substantially devoid of chlorine in a first elongated chamber of a first furnace, the first elongated chamber having a single isothermal hot zone maintained at a doping temperature between 800°
C. and 1200°
C. to obtain a fluorine-doped soot preform,wherein the first elongated chamber is a first muffle tube of generally cylindrical shape arranged vertically and the first furnace comprises a heater arranged peripherally to the first muffle tube, the heater defining the single isothermal zone, wherein the first furnace comprises a gas inlet port positioned above the heater and an inner pipe having an inlet end opening and an outlet end opening, the inner pipe being fluidly connected to the gas inlet port through its inlet end opening, wherein the inner pipe extends vertically downward inside the first muffle tube for guiding an inlet gas flow to a lower portion of the first muffle tube, and wherein exposing a soot preform to an atmosphere containing a fluorine-containing gas comprises feeding the fluorine-containing gas into an inlet pipe through the gas inlet port to the outlet end opening for the outlet gas flow; (ii) dehydrating the fluorine-doped soot preform by exposing it to an atmosphere containing a chlorine-containing gas and being substantially devoid of fluorine in a second elongated chamber of a second furnace, the second elongated chamber having an upper hot zone maintained at a dehydration temperature between 1000°
C. and 1350°
C. and a lower hot zone maintained at a consolidation temperature between 1500°
C. and 1650°
C., wherein dehydration takes place in the upper hot zone of the second furnace; and(iii) consolidating the fluorine-doped soot preform by moving it into the lower hot zone of the second furnace to form a fluorine-doped glass preform. - View Dependent Claims (20)
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Specification