Gte Laboratories Incorporated

Alfred D Briere

Richard M Klein

An optical fiber drawing furnace includes a graphite element of generally cylindrical shape with a reduced central cross-sectional configuration having a flange at opposite ends thereof and having an axial hole therethrough including a central internal element chamber for receiving a glass preform, means for water cooling the flanges, and means for applying electric power across the flanges to resistively heat the reduced cross-sectional configuration and, hence, the central internal element chamber so that an optical fiber can be drawn from the preform. The invention relates to prolonging the useful life of the graphite element by suitable methods and apparatus. The water used for cooling the flanges can be regulated to a temperature such as to avoid condensation of atmospheric moisture within the room (in which the furnace is located) upon the furnace. The application of electric power across the flanges can be increased and decreased at a gradual rate so as to avoid thermal shock to the graphite element.

Methods for prolonging the useful life of a graphite element in an

A furnace for drawing optical fiber includes a graphite element of generally cylindrical shape with a reduced central cross-sectional configuration having a flange at opposite ends thereof and having an axial hole therethrough including a central internal element chamber for receiving a glass preform, means for heating the reduced central cross-sectional configuration, and, hence, the central internal element chamber, so that an optical fiber can be drawn from the preform. The invention relates to providing a relationship between the internal diameter of the central internal element chamber and the inner diameter of the exhaust tubes so as to minimize gas turbulence within the central internal element chamber and thereby control the diameter of an optical fiber being drawn. The relationships can be such that the internal diameter of the central internal element chamber and the inner diameters of an input exhaust tube and an exit exhaust tube are substantially equal. The transitions from an enlarged hole to the central internal element chamber can be by way of tapers.

Graphite element for use in a furnace for drawing optical fiber

A self-centering device supports a generally cylindrically shaped workpiece. A pair of parallel, substantially horizontal shares are mounted within a mounting frame and traverse an opening therewithin. A pair of rolling bearings are adapted for reciprocating movement axially along the two shafts, respectively, with a first connecting rod coupled to the two bearings, so that the resulting rod and bearings can be reciprocated in the direction parallel to the axes of the shafts. In similar fashion, two other rolling bearings are adapted for reciprocating movement axially along the shafts, respectively, with a second connecting rod coupled to the latter bearings so that the resulting rod and latter bearing combinations can be reciprocated in the direction parallel to the axes of the shafts. A first connecting rod bearing is adapted for reciprocating movement axially along the first connecting rod. A second connecting rod bearing is adapted for reciprocating movement axially along the second connecting rod. A mounting carriage, coupled to the two connecting rod bearings, house a spherical-seated, self-aligning bearing which can support the workpiece so the axis of the workpiece can be moved at an appreciable angle in any direction, thus supporting the workpiece against the resultant of a force of tension along a generally downward direction and of a force due to gravity. Means can be provided for providing movement to the frame so that the preform can be lowered into a furnace. The preform is self-centering with respect to the device without the necessity of operator intervention and without the necessity of monitoring and feedback of electrical signals to the device.

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Worcester, MA, United States of America

Alfred D Briere