Method of applying coating liquid to an optical fiber

Abstract

A method of applying a coating liquid to an optical fiber is described. An optical fiber is drawn through a guide die into a pressurized coating chamber and through the pressurized coating chamber to a sizing die. The pressurized coating chamber contains a coating liquid. The method includes directing coating liquid in a direction transverse to the processing pathway of the optical fiber in the pressurized coating chamber. The transverse flow of coating liquid counteracts detrimental effects associated with gyres that form in the pressurized coating chamber during the draw process. Benefits of the transverse flow include removal of bubbles, reduction in the temperature of the gyre, improved wetting, homogenization of the properties of the coating liquid in the pressurized coating chamber, and stabilization of the meniscus.

What is claimed is: 
     
         1 . A system for processing an optical fiber comprising:
 a coating chamber for holding a coating liquid for coating an optical fiber, the coating chamber comprising a fiber entrance and a fiber exit, the fiber entrance and fiber exit defining a drawing direction of an optical fiber through the coating liquid in the coating chamber;   an inlet for delivering a transverse flow of the coating liquid into the coating chamber, the transverse flow of the coating liquid flowing in a direction transverse to the drawing direction; and;   an outlet for removing the transverse flow of the coating liquid from the coating chamber;   wherein the inlet and the outlet are distinct from the fiber entrance and the fiber exit.   
     
     
         2 . The system of  claim 1 , wherein the fiber entrance comprises a guide die for guiding the optical fiber into the coating chamber and the fiber exit comprises a sizing die for delivering the optical fiber from the coating chamber. 
     
     
         3 . The system of  claim 1 , wherein a cross-sectional dimension of the inlet is greater than 30% of the distance between the fiber entrance and the fiber exit. 
     
     
         4 . The system of  claim 1 , wherein a cross-sectional dimension of the inlet is greater than 50% of the distance between the fiber entrance and the fiber exit. 
     
     
         5 . The system of  claim 1 , wherein a cross-sectional dimension of the inlet is greater than 70% of the distance between the fiber entrance and the fiber exit. 
     
     
         6 . The system of  claim 1 , wherein the coating chamber is pressurized to a pressure greater than 0 psig. 
     
     
         7 . The system of  claim 1 , wherein the coating chamber is pressurized to a pressure of at least 1.0 psig. 
     
     
         8 . The system of  claim 1 , wherein the coating chamber is pressurized to a pressure of at least 5.0 psig. 
     
     
         9 . The system of  claim 1 , wherein the coating chamber is pressurized to a pressure greater than  10  psig. 
     
     
         10 . The system of  claim 1 , wherein the transverse flow has a flow rate greater than 0.1 cm 3 /s. 
     
     
         11 . The system of  claim 1 , wherein the transverse flow has a flow rate greater than 0.3 cm 3 /s. 
     
     
         12 . The system of  claim 1 , wherein the transverse flow has a flow rate greater than 1.0 cm 3 /s. 
     
     
         13 . The system of  claim 1 , wherein the outlet is configured to remove the transverse flow at a rate greater than 0.1 cm 3 /s. 
     
     
         14 . The system of  claim 1 , wherein the outlet is configured to remove the transverse flow at a rate greater than 0.3 cm 3 /s. 
     
     
         15 . The system of  claim 1 , wherein the outlet is configured to remove the transverse flow at a rate greater than 0.5 cm 3 /s.