# US 11,029,467 B2 · Fiber coupler > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 11,029,467 B2 - Document ID: US11029467B2 - Status: Granted - Kind: B2 - Application number: 16/587,834 - Filed: 2019-09-30 - Published: 2020-04-16 - Granted: 2021-06-08 - Earliest claimed: 2018-10-11 - Assignees: Lumentum Operations LLC - Applicants: Lumentum Operations LLC - Inventors: Martin H. Muendel; Richard D. Faulhaber; James Lefort; James J. Morehead; Vincent Petit; Simonette Pierrot; Kyle R. Schneider - Web page: https://patentgrep.com/patent/US11029467B2 ## CPC - G02B 6/32: having lens focusing means {positioned between opposed fibre ends (with lens being an integral part of the single fibre end G02B6/262)} - C03C 3/04: containing silica - G02B 6/122: Basic optical elements, e.g. light-guiding paths - G02B 6/255: Splicing of light guides, e.g. by fusion or bonding - G02B 6/2551: {using thermal methods, e.g. fusion welding by arc discharge, laser beam, plasma torch} - G02B 6/262: {Optical details of coupling light into, or out of, or between fibre ends, e.g. special fibre end shapes or associated optical elements} - G02B 6/4204: {the coupling comprising intermediate optical elements, e.g. lenses, holograms (encapsulated active devices H01S5/02208)} - C03B 2201/06: Doped silica-based glasses - G02B 2006/12147: {Coupler} - G02B: OPTICAL ELEMENTS, SYSTEMS OR APPARATUS - C03C: CHEMICAL COMPOSITION OF GLASSES, GLAZES OR VITREOUS ENAMELS; SURFACE TREATMENT OF GLASS; SURFACE TREATMENT OF FIBRES OR FILAMENTS MADE FROM GLASS, MINERALS OR SLAGS; JOINING GLASS TO GLASS OR OTHER MATERIALS - C03B: MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES ## Abstract A method may include performing an active alignment to enable optical coupling between a first optical fiber and a second optical fiber via an imaging structure. An end of the first optical fiber may be at a first location on a first surface of the imaging structure. The first location may be a first transverse offset distance from an axis of the imaging structure. An end of the second optical fiber may be at a second location of the first surface of the imaging structure. The second location may be a second transverse offset distance from the axis of the imaging structure. The method may include fusion splicing the end of the first optical fiber at the first location on the first surface of the imaging structure, and fusion splicing the end of the second optical fiber at the second location on the first surface of the imaging structure. ## Claims ### Claim 1 A method, comprising: providing a first optical fiber and a second optical fiber such that an end of the first optical fiber is at a fixed position with respect to an end of the second optical fiber; performing an active alignment to enable optical coupling between the first optical fiber and the second optical fiber via a curved endcap structure with a fixed refractive index, wherein a center of curvature of the curved endcap structure is located on a first surface of the curved endcap structure, and wherein, as a result of the active alignment: an end of the first optical fiber is at a first location on the first surface of the curved endcap structure, wherein the first location is at a first transverse offset distance from an axis of the curved endcap structure, and an end of the second optical fiber is at a second location of the first surface of the curved endcap structure, wherein the second location is at a second transverse offset distance from the axis of the curved endcap structure; and concurrently fusion splicing the end of the first optical fiber at the first location on the first surface and the end of the second optical fiber at the second location on the first surface, wherein at least one of: the curved endcap structure is formed from undoped fused silica, or the first optical fiber is a pump input fiber and the second optical fiber is an amplifier fiber. ### Claim 2 (depends on 1) The method of claim 1, wherein the concurrent fusion splicing of the end of the first optical fiber at the first location and the end of the second optical fiber at the second location is performed using a single heat source. ### Claim 3 (depends on 1) The method of claim 1, further comprising: packaging the first optical fiber, the second optical fiber, and the curved endcap structure to provide strain relief or heatsinking. ### Claim 4 (depends on 1) The method of claim 1, wherein the curved endcap structure is formed from the undoped fused silica. ### Claim 5 (depends on 1) The method of claim 1, wherein the first transverse offset distance matches the second transverse offset distance. ### Claim 6 (depends on 1) The method of claim 1, wherein the first optical fiber is the pump input fiber and the second optical fiber is the amplifier fiber. ### Claim 7 (depends on 6) The method of claim 6, wherein the curved endcap structure comprises a dichroic coating at a second surface of the curved endcap structure. ### Claim 8 (depends on 6) The method of claim 6, wherein the pump input fiber is a multimode fiber and the amplifier fiber is a double-clad fiber or a triple-clad fiber. ### Claim 9 (depends on 6) The method of claim 6, wherein the pump input fiber and the amplifier fiber are single-clad and single-mode fibers. ### Claim 10 A method, comprising: fusion splicing an end of a first optical fiber at a first location on a first surface of a curved endcap structure with a fixed refractive index, wherein a center of curvature of the curved endcap structure is located on the first surface of the curved endcap structure, and wherein the first location is at a first transverse offset distance from an axis of the curved endcap structure; performing an active alignment to enable optical coupling between the first optical fiber and a second optical fiber via the curved endcap structure, wherein, as a result of the active alignment, an end of the second optical fiber is at a second location on the first surface of the curved endcap structure, wherein the second location is at a second transverse offset distance from the axis of the curved endcap structure; and fusion splicing the end of the second optical fiber at the second location on the first surface of the curved endcap structure, wherein at least one of: the curved endcap structure is formed from undoped fused silica, or the first optical fiber is a pump input fiber and the second optical fiber is an amplifier fiber. ### Claim 11 (depends on 10) The method of claim 10, wherein the fusion splicing of the end of the first optical fiber at the first location and the fusion splicing of the end of the second optical fiber at the second location is performed using a carbon dioxide laser. ### Claim 12 (depends on 10) The method of claim 10, further comprising: packaging the first optical fiber, the second optical fiber, and the curved endcap structure to provide strain relief or heatsinking. ### Claim 13 (depends on 10) The method of claim 10, wherein the first transverse offset distance matches the second transverse offset distance. ### Claim 14 (depends on 10) The method of claim 10, wherein the first optical fiber is the pump input fiber and the second optical fiber is the amplifier fiber. ### Claim 15 A method, comprising: performing an active alignment to enable optical coupling between a first optical fiber and a second optical fiber via a curved endcap structure with a fixed refractive index, wherein a center of curvature of the curved endcap structure is located on a first surface of the curved endcap structure, wherein an end of the first optical fiber is at a first location on the first surface of the curved endcap structure, the first location being at a first transverse offset distance from an axis of the curved endcap structure, and wherein an end of the second optical fiber is at a second location on the first surface of the curved endcap structure, the second location being at a second transverse offset distance from the axis of the curved endcap structure; fusion splicing the end of the first optical fiber at the first location on the first surface of the curved endcap structure; and fusion splicing the end of the second optical fiber at the second location on the first surface of the curved endcap structure, wherein at least one of: the curved endcap structure is formed from undoped fused silica, or the first optical fiber is a pump input fiber and the second optical fiber is an amplifier fiber. ### Claim 16 (depends on 15) The method of claim 15, wherein the fusion splicing of the end of the first optical fiber at the first location and the end of the second optical fiber at the second location is performed using a single heat source. ### Claim 17 (depends on 15) The method of claim 15, further comprising: packaging the first optical fiber, the second optical fiber, and the curved endcap structure to provide strain relief or heatsinking. ### Claim 18 (depends on 15) The method of claim 15, wherein the curved endcap structure is formed from the undoped fused silica. ### Claim 19 (depends on 15) The method of claim 15, wherein the first transverse offset distance matches the second transverse offset distance. ### Claim 20 (depends on 15) The method of claim 15, wherein the first optical fiber is the pump input fiber and the second optical fiber is the amplifier fiber.