# US 11,079,589 B2 · Optical fibre > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 11,079,589 B2 - Document ID: US11079589B2 - Status: Granted - Kind: B2 - Application number: 16/633,831 - Filed: 2018-07-11 - Published: 2020-07-30 - Granted: 2021-08-03 - Earliest claimed: 2017-07-24 - Assignees: Centre National De La Recherche Scientifique; Universite De Limoges - Applicants: Centre National De La Recherche Scientifique; Universite De Limoges - Inventors: Abdel Fetah Benabid - Web page: https://patentgrep.com/patent/US11079589B2 ## CPC - G02B 6/02347: {Longitudinal structures arranged to form a regular periodic lattice, e.g. triangular, square, honeycomb unit cell repeated throughout cladding} - G02B 23/2469: {using optical fibres} - A61B 1/00167: {Details of optical fibre bundles, e.g. shape or fibre distribution} - A61B 1/043: {for fluorescence imaging} - A61B 1/07: using light-conductive means, e.g. optical fibres - A61B 18/22: the beam being directed along or through a flexible conduit, e.g. an optical fibre; {Couplings or} hand-pieces therefor - C03B 37/0122: {for making preforms of photonic crystal, microstructured or holey optical fibres} - G02B 6/02328: {Hollow or gas filled core} - G02B 6/02338: {Structured core, e.g. core contains more than one material, non-constant refractive index distribution in core, asymmetric or non-circular elements in core unit, multiple cores, insertions between core and clad} - G02B 6/032: with non solid core or cladding {(G02B6/02295 takes precedence)} - G02B 23/26: using light guides {(for illumination G02B23/2469)} - A61B 2017/00057: {Light} - A61B 2018/00577: {Ablation} - A61B 2018/2211: {Plurality of fibres} - A61B 2018/2227: {Hollow fibres} - C03B 2203/14: Non-solid, i.e. hollow products, e.g. hollow clad or with core-clad interface - C03B 2203/16: Hollow core - C03B 2203/42: Photonic crystal fibres, e.g. fibres using the photonic bandgap PBG effect, microstructured or holey optical fibres - G01N 21/6456: {Spatial resolved fluorescence measurements; Imaging} - G01N 2021/6484: {Optical fibres} - G02F 1/365: in an optical waveguide structure (G02F1/377, {G02F1/395} take precedence) - G02B: OPTICAL ELEMENTS, SYSTEMS OR APPARATUS - A61B: DIAGNOSIS; SURGERY; IDENTIFICATION (usefulness limited to only animals A61D) - C03B: MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES - G01N: INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES (measuring or testing apparatus or processes other than immunoassay, involving enzymes or microorganisms C12M, C12Q) - G02F: OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS ## Abstract An optical fibre for an ultrafast laser endoscope including at least the following structures: a hollow core, the periphery of which has an order of symmetry of at least six when considering axes of symmetry passing through the centre of the core and through the centre of convex shapes, seen from the centre of the core, the convex shapes at least partly making up the periphery of the core; an intermediate layer of cellular structure surrounding the core; a light conducting peripheral structure surrounding the intermediate layer of cellular structure; and an outer sheath surrounding the light-conducting peripheral structure. A particular advantage of the optical fibre is that it optimizes the emission of a high-power flux associated with fluorescence collection. ## Claims ### Claim 1 An optical fibre comprising: a hollow core the periphery of which has an order of symmetry of at least six when considering axes of symmetry passing through the centre of the core and through the centre of convex shapes, seen from the centre of the core, said convex shapes at least partially composing the periphery of the core, the periphery of the core has a shape resulting from a combination of elliptical arcs that are convex seen from the centre of the core; an intermediate layer having a cellular structure surrounding the core, said intermediate layer having a cellular structure having walls the thickness of which is comprised between 100 nm and 2000 nm, the cellular structure being a Kagome structure, the combination of elliptical arcs constituting a boundary between the Kagome structure and the core; a light-conducting peripheral structure surrounding the intermediate layer having a cellular structure; and an external cladding surrounding the light-conducting peripheral structure. ### Claim 2 (depends on 1) The optical fibre according to claim 1, characterized in that the intermediate layer having a cellular structure has a thickness comprised between 10 μm and 75 μm. ### Claim 3 (depends on 1) The optical fibre according to claim 1, characterized in that the light-conducting peripheral structure has a thickness comprised between 1 μm and 10 μm. ### Claim 4 (depends on 1) The optical fibre according to claim 1, characterized in that the minimum radius of the periphery of the core is comprised between 20 μm and 60 μm. ### Claim 5 (depends on 1) The optical fibre according to claim 1, characterized in that the light-conducting peripheral structure has a refractive index greater than that of the external cladding. ### Claim 6 (depends on 1) The optical fibre according to claim 1, characterized in that the light-conducting peripheral structure has a numerical aperture greater than 0.1. ### Claim 7 (depends on 1) The optical fibre according to claim 1, characterized in that the light-conducting peripheral structure, is a continuous annular peripheral structure having a thickness comprised between 2 μm and 8 μm. ### Claim 8 (depends on 1) The optical fibre according to claim 1, characterized in that the elliptical arcs are parameterized by a coefficient b=d/r, where d is a first radius of the ellipse directed towards the centre of the core and r is a second radius of the ellipse substantially perpendicular to d, b being comprised between 0.4 and 1.5. ### Claim 9 (depends on 1) The optical fibre according to claim 1, characterized in that the combination of elliptical arcs comprises alternately a first elliptical arc the smallest distance to the centre of the core of which is a radius Rin, and a second elliptical arc the smallest distance to the centre of the core of which is a radius Rout, with Rin/Rout comprised between 0.6 and 0.9. ### Claim 10 (depends on 1) The optical fibre according to claim 1, characterized in that the Kagome structure has a thickness comprised between at least one element having Kagome structure and four elements having Kagome structure, a Kagome structure element having a diameter comprised between 10 μm and 25 μm. ### Claim 11 (depends on 1) The optical fibre according to claim 1, characterized in that each element of the Kagome structure is delimited by a set of walls called bridges, said bridges have a refractive index less than that of the external cladding or substantially equal to that of the external cladding to plus or minus 10%. ### Claim 12 (depends on 11) The optical fibre according to claim 11, characterized in that the bridges of the Kagome structure have a thickness comprised between λc/2.6 and λc/2.8, λc being a wavelength to be guided. ### Claim 13 (depends on 1) The optical fibre according to claim 1, characterized in that the light-conducting peripheral structure comprises blocks the thickness of which is greater than the thickness of the bridges of the Kagome structure and the refractive index of which is greater than the refractive index of the external cladding, said blocks being situated between the Kagome structure and the external cladding. ### Claim 14 (depends on 1) The optical fibre according to claim 1, characterized in that it comprises, between the external cladding and the light-conducting peripheral structure, a gas cladding having an annular structure, supported by glass bridges, extending radially from the exterior of said optical fibre in the direction of the centre of the optical fibre. ### Claim 15 (depends on 14) The optical fibre according to claim 14, characterized in that the bridges of the gas cladding have a thickness comprised between 100 nm and 2000 nm. ### Claim 16 (depends on 14) The optical fibre according to claim 14, characterized in that the Kagome structure is in contact with the light-conducting peripheral structure, itself in contact with the gas cladding which is itself in contact with the external cladding. ### Claim 17 (depends on 14) The optical fibre according to claim 14, further including a plurality of hollow cylinders and characterized in that each of the hollow cylinders is in contact with the light-conducting peripheral structure, itself in contact with the gas cladding, said gas cladding being in contact with the external cladding. ### Claim 18 (depends on 1) The optical fibre according to claim 1, characterized in that the intermediate layer having a cellular structure comprises a single layer of hollow cylinders made from dielectric material at a distance from one another. ### Claim 19 (depends on 18) The optical fibre according to claim 18, characterized in that the walls of the hollow cylinders have a thickness comprised between 100 nm and 2000 nm. ### Claim 20 (depends on 18) The optical fibre according to claim 18, characterized in that each hollow cylinder is in contact with the light-conducting peripheral structure or the internal cladding. ### Claim 21 An optical fibre comprising: a hollow core the periphery of which has an order of symmetry of at least six when considering axes of symmetry passing through the centre of the core and through the centre of convex shapes, seen from the centre of the core, said convex shapes at least partially composing the periphery of the core; an intermediate layer having a cellular structure surrounding the core, said intermediate layer having a cellular structure having walls the thickness of which is comprised between 100 nm and 2000 nm; a light-conducting peripheral structure surrounding the intermediate layer having a cellular structure; an external cladding surrounding the light-conducting peripheral structure; and an internal cladding between the intermediate layer having a cellular structure and the light-conducting peripheral structure, the internal cladding being in contact with the intermediate layer that has a cellular structure. ### Claim 22 (depends on 21) The optical fibre according to claim 21, characterized in that the internal cladding is in contact with the light-conducting peripheral structure, said light-conducting peripheral structure being in contact with the external cladding. ### Claim 23 (depends on 14) The optical fibre according to claim 14, characterized in that the internal cladding has a thickness comprised between 100 nm and 8 μm. ### Claim 24 (depends on 21) The optical fibre according to claim 21, characterized in that the intermediate layer having a cellular structure has a thickness comprised between 10 μm and 75 μm. ### Claim 25 (depends on 21) The optical fibre according to claim 21, characterized in that the light-conducting peripheral structure has a thickness comprised between 1 μm and 10 μm. ### Claim 26 (depends on 21) The optical fibre according to claim 21, characterized in that the minimum radius of the periphery of the core is comprised between 20 μm and 60 μm. ### Claim 27 (depends on 21) The optical fibre according to claim 21, characterized in that the light-conducting peripheral structure has a refractive index greater than that of the external cladding. ### Claim 28 (depends on 21) The optical fibre according to claim 21, characterized in that the light-conducting peripheral structure has a numerical aperture greater than 0.1. ### Claim 29 (depends on 21) The optical fibre according to claim 21, characterized in that the light-conducting peripheral structure, is a continuous annular peripheral structure having a thickness comprised between 2 μm and 8 μm.