Patent ID: 6527986
Filing Date: 2003-03-04
Classification: B29C,B29D,B29L

Abstract:
A process for fabricating plastic optical fiber, comprising the steps of:(a) providing a core polymer reservoir comprising a molten core polymer, the core polymer reservoir comprising a core fluid inlet and a core polymer outlet, and providing a cladding polymer reservoir comprising a molten cladding polymer, the cladding polymer reservoir comprising a cladding fluid inlet and a cladding polymer outlet, wherein the molten core polymer, the molten cladding polymer, or both the molten core polymer and the molten cladding polymer optionally comprise one or more dopants; (b) directing fluid into the core fluid inlet and into the cladding fluid inlet, such that the fluid causes a pressure to be exerted on the molten core polymer and on the molten cladding polymer; (c) bringing at least a portion of the molten core polymer to a substantially uniform temperature in at least one of a portion of the core polymer reservoir and a core thermal homogenizer section connected directly or indirectly to the core polymer reservoir; bringing at least a portion of the molten cladding polymer to a substantially uniform temperature in at least one of a portion of the cladding polymer reservoir and a cladding thermal homogenizer section connected directly or indirectly to the cladding polymer reservoir, to provide thermally homogenized molten core polymer and thermally homogenized molten cladding polymer; directing the thermally homogenized molten core polymer into a core flow restrictor section; and directing the thermally homogenized molten cladding polymer into a cladding flow restrictor section, wherein the temperature of at least one of the portion of the core polymer reservoir and the core thermal homogenizer section is adjustable, and wherein the temperature of the core flow restrictor section is adjustable, such that the flow characteristics of the molten core polymer are capable of being controlled by adjusting the temperatures, and wherein the temperature of at least one of the portion of the cladding polymer reservoir and the cladding thermal homogenizer section is adjustable, and wherein the temperature of the cladding flow restrictor section is adjustable, such that the flow characteristics of the molten cladding polymer are capable of being controlled by adjusting the temperatures; (d) directing the molten core polymer and molten cladding polymer from the core and cladding flow restrictor sections into a first extrusion cross-head, the first extrusion cross-head providing a polymer flow comprising the molten core polymer surrounded by the molten cladding polymer; (e) if the one or more dopants are present, directing the polymer flow comprising the molten core polymer surrounded by the molten cladding polymer into a diffusion section, wherein at least a portion of the one or more dopants diffuse from the molten core polymer into the molten cladding polymer, from the molten cladding polymer into the molten core polymer, or from the molten core polymer into the molten cladding polymer and from the molten cladding polymer into the molten core polymer; and (f) directing the polymer flow into a die and drawing the plastic optical fiber from the die.