# US 10,370,280 B2 · Method of making optical fibers with multiple openings > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,370,280 B2 - Document ID: US10370280B2 - Status: Granted - Kind: B2 - Application number: 15/722,385 - Filed: 2017-10-02 - Published: 2018-04-05 - Granted: 2019-08-06 - Earliest claimed: 2016-10-03 - Assignees: The United States of America as represented by the Secretary of the Navy - Applicants: The United States of America, as represented by the Secretary of the Navy - Inventors: Daniel J. Gibson; Rafael R. Gattass; Daniel L. Rhonehouse; Shyam S. Bayya; L. Brandon Shaw; Jasbinder S. Sanghera - Web page: https://patentgrep.com/patent/US10370280B2 ## CPC - B29C 48/05: Filamentary, e.g. strands - B29C 48/11: comprising two or more partially or fully enclosed cavities, e.g. honeycomb-shaped - B29C 48/30: Extrusion nozzles or dies (extrusion characterised by the shape or cross-section of the extruded article B29C48/03) - B29C 48/3003: {Materials, coating or lining therefor} - B29C 48/32: with annular openings, e.g. for forming tubular articles - B29C 48/345: Extrusion nozzles comprising two or more adjacently arranged ports, for simultaneously extruding multiple strands, e.g. for pelletising - C03B 17/04: Forming tubes or rods by drawing from stationary or rotating tools or from forming nozzles - C03B 37/01274: {by extrusion or drawing} - C03B 37/02781: {Hollow fibres, e.g. holey fibres} - C03B 37/0279: {Photonic crystal fibres or microstructured optical fibres other than holey optical fibres} - G02B 6/02042: {Multicore optical fibres} - B29C 48/0018: {combined with shaping by orienting, stretching or shrinking, e.g. film blowing (B29C48/0017 takes precedence)} - B29C 48/09: Articles with cross-sections having partially or fully enclosed cavities, e.g. pipes or channels - C03B 2201/86: Chalcogenide glasses, i.e. S, Se or Te glasses - C03B 2201/88: Chalcohalide glasses, i.e. containing one or more of S, Se, Te and one or more of F, Cl, Br, I - C03B 2203/42: Photonic crystal fibres, e.g. fibres using the photonic bandgap PBG effect, microstructured or holey optical fibres - G02B 6/02366: {Single ring of structures, e.g. "air clad"} - B29C: SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING (making preforms B29B11/00; making laminated products by combining previously unconnected layers which become one product whose layers will remain together B32B37/00 - B32B41/00) - C03B: MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES - G02B: OPTICAL ELEMENTS, SYSTEMS OR APPARATUS ## Abstract A method of making an optical fiber with multiple openings comprising the steps of fabricating an extrusion die using additive manufacturing such that the extrusion die has a plurality of channels that combine inside the die into another set of channels, extruding a glass, forming a fiber optic preform having a plurality of longitudinal openings that run the entire length, attaching a barrier layer for pressure application, and stretching the preform into an optical fiber with multiple openings. An extrusion die comprising an additive manufactured material, having a proximal side having openings and having a distal side having openings, wherein the openings of the proximal side are of feed channels, wherein the openings of the distal side are of forming channels, and wherein in side the body of the die, two of the feed channels combine the forming channels. ## Claims ### Claim 1 A method of making an optical fiber with multiple openings, comprising the steps of: fabricating an extrusion die using at least one additive manufacturing technique such that the extrusion die has a first set of plurality of channels that combine inside the die into a second set of plurality of channels with a different set of shapes and sizes; extruding a glass through the extrusion die; forming a fiber optic preform having a plurality of longitudinal openings that run the entire length of the fiber optic preform; attaching a barrier layer to the fiber optic preform to form a series of channels to which pressure can be applied by a gas; wherein each channel has a pressure that is independently controlled; and stretching the fiber optic preform at an elevated temperature into an optical fiber with multiple openings. ### Claim 2 (depends on 1) The method of making an optical fiber with multiple openings of claim 1, wherein the step of extruding comprises softening the glass to reach a viscosity in the range of 1011 to 106 Pa*sec. ### Claim 3 (depends on 1) The method of making an optical fiber with multiple openings of claim 1, wherein the step of extruding comprises softening the glass to reach a viscosity in the range of 108 to 1010 Pa*sec. ### Claim 4 (depends on 1) The method of making an optical fiber with multiple openings of claim 1, wherein the step of stretching comprises heating the fiber optic preform such that the viscosity of the fiber optic preform reaches 107 to 103 Pa*sec. ### Claim 5 (depends on 1) The method of making an optical fiber with multiple openings of claim 1, wherein the step of stretching comprises heating the fiber optic preform such that the viscosity of the fiber optic preform reaches 105 to 106 Pa*sec. ### Claim 6 A method of making an optical fiber with multiple openings, comprising the steps of: designing a fiber structure; designing and fabricating an extrusion die using additive manufacturing or three-dimensional (3D) printing; wherein the extrusion die has a first set of plurality of channels that combine inside the die into a second set of plurality of channels with a different set of shapes and sizes; wherein each channel has a pressure that is independently controlled; extruding a preform from an IR-transparent glass from the additive-manufactured die; and stretching the preform into an optical fiber with multiple openings. ### Claim 7 (depends on 6) The method of making an optical fiber with multiple openings of claim 6 wherein the IR-transparent glass is softened. ### Claim 8 (depends on 6) The method of making an optical fiber with multiple openings of claim 6, further comprising the steps of: heating the IR-transparent glass prior to the step of extruding a preform, wherein said heating the IR-transparent glass comprising heating to a temperature of about 350° C. for about 10 hours. ### Claim 9 (depends on 6) The method of making an optical fiber with multiple openings of claim 6, wherein the step of extruding comprises softening the glass to reach a viscosity in the range of 1011 to 106 Pa*sec. ### Claim 10 (depends on 6) The method of making an optical fiber with multiple openings of claim 6, wherein the step of stretching comprises heating the fiber optic preform such that the viscosity of the fiber optic preform reaches 107 to 103 Pa*sec.