Method for stretching refractory bodies
AssigneeLucent Technologies Inc.
InventorsJames W. Fleming, Michael L. Pearsall
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Abstract
A refractory body having reduced optical attenuation, and a method for making same, is disclosed. A refractory body is exposed to a high-temperature oxygen-containing plasma. A drawing force is applied to the body, elongating the body to form a rod of reduced diameter. The source of the plasma is moved in a direction opposite to the applied drawing force, and, preferably, has a reciprocating component of motion to spread the zone of heating. The method is particularly useful in manufacturing optical fiber core rods having low optical attenuation.
Claims22
A method for drawing a refractory body comprising the steps of:
- exposing a refractory body to a high-temperature plasma;
- applying a drawing force to the refractory body;
- and
- moving the high-temperature plasma and the refractory body longitudinally relative to one another at a non-zero average rate.
A method for manufacturing an optical core rod comprising the steps of:
- providing a core rod preform having a core and a cladding, wherein the ratio of the diameter of the cladding to the core is less than about 5;
- exposing the core rod preform to a high-temperature plasma;
- applying a drawing force to the core rod preform;
- and
- moving the high-temperature plasma longitudinally in relation to the core rod preform at a non-zero average rate.
A method for forming an optical core rod having low optical attenuation at at least one wavelength, comprising the steps of:
- providing a core rod preform having a core and a cladding, wherein the ratio of the diameter of the cladding to the core is less than about 5;
- removing moisture from the core rod preform;
- and
- applying a drawing force to the core rod preform, which, when suitably softened, elongates to form an optical core rod.
An optical core rod prepared from an optical core rod preform, the optical core rod comprising:
- a glass core surrounded by a glass cladding, wherein the ratio of the diameter of the cladding to the diameter of the core is less than about 5, and, wherein,
- the moisture content of the optical core rod is sufficiently low so that its optical attenuation is less than about 0.31 dB per kilometer at a wavelength 1385 nanometers.
An optical core rod comprising:
- a glass core formed by removing moisture from a core rod preform and applying a drawing force thereto;
- and
- a glass cladding surrounding the glass core.
Dependencies are inferred from the claim text.