WO2015126479A1 - Guide d'ondes optiques multi-cœur pour une détection de multiples paramètres - Google Patents

Guide d'ondes optiques multi-cœur pour une détection de multiples paramètres Download PDF

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Publication number
WO2015126479A1
WO2015126479A1 PCT/US2014/065417 US2014065417W WO2015126479A1 WO 2015126479 A1 WO2015126479 A1 WO 2015126479A1 US 2014065417 W US2014065417 W US 2014065417W WO 2015126479 A1 WO2015126479 A1 WO 2015126479A1
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WO
WIPO (PCT)
Prior art keywords
optical waveguides
core
large diameter
different
cladding
Prior art date
Application number
PCT/US2014/065417
Other languages
English (en)
Inventor
Chrisopher S. BALDWIN
Thomas W. Engel
Original Assignee
Weatherford/Lamb, Inc.
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority claimed from US14/081,045 external-priority patent/US20140241681A1/en
Application filed by Weatherford/Lamb, Inc. filed Critical Weatherford/Lamb, Inc.
Priority to GB1605800.0A priority Critical patent/GB2535049B/en
Publication of WO2015126479A1 publication Critical patent/WO2015126479A1/fr

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Classifications

    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
    • G02B6/24—Coupling light guides
    • G02B6/42—Coupling light guides with opto-electronic elements
    • G02B6/4201—Packages, e.g. shape, construction, internal or external details
    • G02B6/4248—Feed-through connections for the hermetical passage of fibres through a package wall
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
    • G02B6/44—Mechanical structures for providing tensile strength and external protection for fibres, e.g. optical transmission cables
    • G02B6/4401—Optical cables
    • G02B6/4415—Cables for special applications
    • G02B6/4427—Pressure resistant cables, e.g. undersea cables
    • G02B6/4428—Penetrator systems in pressure-resistant devices
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01L—MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE
    • G01L11/00—Measuring steady or quasi-steady pressure of a fluid or a fluent solid material by means not provided for in group G01L7/00 or G01L9/00
    • G01L11/02—Measuring steady or quasi-steady pressure of a fluid or a fluent solid material by means not provided for in group G01L7/00 or G01L9/00 by optical means
    • G01L11/025—Measuring steady or quasi-steady pressure of a fluid or a fluent solid material by means not provided for in group G01L7/00 or G01L9/00 by optical means using a pressure-sensitive optical fibre
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
    • G02B6/02—Optical fibres with cladding with or without a coating
    • G02B6/02042—Multicore optical fibres
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
    • G02B6/24—Coupling light guides
    • G02B6/36—Mechanical coupling means
    • G02B6/38—Mechanical coupling means having fibre to fibre mating means
    • G02B6/3807—Dismountable connectors, i.e. comprising plugs
    • G02B6/381—Dismountable connectors, i.e. comprising plugs of the ferrule type, e.g. fibre ends embedded in ferrules, connecting a pair of fibres
    • G02B6/3816—Dismountable connectors, i.e. comprising plugs of the ferrule type, e.g. fibre ends embedded in ferrules, connecting a pair of fibres for use under water, high pressure connectors
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
    • G02B6/24—Coupling light guides
    • G02B6/36—Mechanical coupling means
    • G02B6/3628—Mechanical coupling means for mounting fibres to supporting carriers
    • G02B6/3664—2D cross sectional arrangements of the fibres
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
    • G02B6/24—Coupling light guides
    • G02B6/36—Mechanical coupling means
    • G02B6/38—Mechanical coupling means having fibre to fibre mating means
    • G02B6/3807—Dismountable connectors, i.e. comprising plugs
    • G02B6/3873—Connectors using guide surfaces for aligning ferrule ends, e.g. tubes, sleeves, V-grooves, rods, pins, balls
    • G02B6/3885—Multicore or multichannel optical connectors, i.e. one single ferrule containing more than one fibre, e.g. ribbon type

Definitions

  • Embodiments of the present invention relate to optical waveguides and, more particularly, to monolithic multi-optical-waveguide feedthroughs and connectors and to multi-core optical waveguides with cores having different structural parameters.
  • FIG. 1 An exemplary sensing assembly for use in harsh environments is disclosed in U.S. Pub. No. 2007/0003206 to Dunphy et al., entitled Optical Waveguide Feedthrough Assembly," which is assigned to the Assignee of the present application and is incorporated herein by reference in its entirety.
  • Dunphy discloses the optical waveguide feedthrough assembly of Figure 1 .
  • the assembly 100 includes a front housing 10 coupled to a back housing 12.
  • An optical waveguide element 14 passes through a passageway 16 common to both housings 10, 12.
  • the passageway 16 is defined by bores extending across the housings 10, 12.
  • the optical waveguide element 14 includes a glass plug 18 defining a large-diameter, cane-based, optical waveguide preferably having an outer diameter of about 3 millimeters (mm) or greater.
  • the glass plug 18 can have appropriate core and cladding dimensions and ratios to provide the desired outer large-diameter.
  • First and second fiber pigtails 19, 20 extend from each end of the glass plug 18.
  • Each of the pigtails 19, 20 includes an optical waveguide such as an optical fiber 26 encased or embedded in a carrier 28 or larger diameter glass structure allowing the fiber 26 to be optically coupled to the glass plug 18.
  • the glass plug 18 has a cone-shaped tapered surface 50 for seating against a complementary tapered seat 51 of the front housing 10. Engagement between the tapered surface 50 and the complementary tapered seat 51 that is located along the passageway 16 forms a seal that seals off fluid communication through the passageway 16.
  • the glass plug 18 can be machined to provide the cone-shaped tapered surface 50. Additionally, the glass plug 18 is preferably biased against the tapered seat 51 using a mechanical preload.
  • a recess 30 formed in one end of the front housing 10 aligns with a corresponding recess 31 in one end of the back housing 12 where the housings 10, 12 are coupled together.
  • the front housing 10 is welded to the back housing 12 along mated features thereof.
  • the housings 10, 12 preferably enclose the glass plug 18, a biasing member such as a first stack of Belleville washers 34, and a plunger 32, which are all disposed within the recesses 30, 31 .
  • the first stack of Belleville washers 34 supply the mechanical preload by pressing the plunger 32 onto an opposite end of the glass plug 18 from the tapered surface 50. Since the plunger 32 is moveable with the glass plug 18, this pressing of the plunger 32 develops a force to bias the glass plug 18 onto the tapered seat 51 of the front housing 10 located along the passageway 16 that passes through the front housing 10. Transfer of force from the plunger 32 to the glass plug 18 can occur directly via an interface 54 between the two, which can include mating conical surfaces.
  • the first stack of Belleville washers 34 compresses between a base shoulder 44 of the recess 31 in the back housing 12 and an outward shoulder 46 of the plunger 32 upon make-up of the front housing 10 to the back housing 12. Once the back housing 12 is welded or otherwise attached to the front housing 10 in order to keep the front and back housings 10, 12 connected, the first stack of Belleville washers 34 maintains the compression that supplies force acting against the plunger 32.
  • the feedthrough assembly 100 further includes a gasket member 52 disposed between the tapered seat 51 and the tapered surface 50 of the glass plug 18.
  • the gasket member 52 comprises an annular gasket.
  • the gasket member 52 may be a gold foil that is shaped to complement the tapered surface 50 and the tapered seat 51 .
  • the gasket member 52 deforms sufficiently to accommodate imperfections on the tapered surface 50 and/or the tapered seat 51 , thereby completing the seal and reducing stress between contacting surfaces due to any imperfections on the surfaces.
  • the housings 10, 12 additionally enclose a cup-shaped backstop sleeve 36, a second stack of Belleville washers 38, a perforated washer 40, and a centering element 42 that are all disposed within the recesses 30, 31 .
  • An outward shoulder 56 of the backstop sleeve 36 is trapped by the end of the front housing 10 and an inward shoulder 57 along the recess 31 in the back housing 12.
  • Contact upon sandwiching of the shoulder 56 of the backstop sleeve 36 provides the point at which the housings 10, 12 are fully mated and can be secured together. Clearance is provided such that the end of the back housing 12 does not bottom out prior to the housings 10, 12 being fully mated.
  • the centering element 42 includes an elastomeric sealing component disposed between the glass plug 18 and the front housing 10 that can act as a backup seal in addition to facilitating alignment of the glass plug 18 with respect to the seat 51 .
  • the pressure in the recesses 30, 31 entering from the second end 24 of the passageway 16 is higher than the pressure entering from the first end 22 of the passageway 16. This pressure differential advantageously causes the centering element 42 to deform and press against the wall of the recess 30 and the wall of the glass plug 18, thereby creating a pressure-energized seal.
  • One or more holes or annular channels 43 can be formed on the outer surface of the high pressure side of the centering element 42.
  • holes or channels 43 facilitate the deformation of the centering element 42 and the formation of the seal between the centering element 42 and the walls of the recess 30 and the glass plug 18. Additionally, the perforated washer 40 enables pressurized fluid to fill the centering element 42 for providing the energized seal.
  • the assembly 100 is suited for feedthrough of a single optical waveguide. If feedthrough of multiple waveguides is desired, a separate assembly may be used for each individual waveguide. This means additional costs and additional space requirements on a production tree, for example.
  • Embodiments of the present invention generally relate to monolithic feedthroughs and connectors supporting multiple optical waveguides and to multi- core optical waveguides with cores having different structural properties for supporting multi-parameter sensing.
  • Such optical waveguides may include optical fibers, large diameter optical waveguides (e.g., cane waveguides), optical sensors, and optical feedthroughs and connectors.
  • Certain advantages ⁇ e.g., reduced strain) provided by the monolithic structures may also be applicable to a single (large diameter) optical waveguide fused into a larger capillary.
  • the apparatus generally includes a plurality of large diameter optical waveguides, each having a core and a cladding, wherein the apparatus is a monolithic structure.
  • the apparatus further includes a body having a plurality of bores with the optical waveguides disposed therein, wherein at least part of the cladding of each of the optical waveguides is fused with the body to form the monolithic structure.
  • Another embodiment of the present invention is a method for forming an apparatus for transmitting light along multiple pathways.
  • the method generally includes positioning a plurality of large diameter optical waveguides, each having a core and a cladding, in a plurality of bores of a body and fusing at least a portion of the cladding of each of the optical waveguides with the body, such that the apparatus resulting therefrom is a monolithic structure.
  • the assembly generally includes a housing, an apparatus for transmitting light along multiple pathways, wherein the apparatus is at least partially disposed in the housing, and one or more annular sealing elements disposed between an inner surface of the housing and an outer surface of the apparatus.
  • the apparatus is a monolithic structure and generally includes a plurality of large diameter optical waveguides, each having a core and a cladding.
  • the apparatus further includes a body having a plurality of bores with the optical waveguides disposed therein, wherein at least a portion of the cladding of each of the optical waveguides is fused with the body to form the monolithic structure.
  • Yet another embodiment of the present invention is a method for forming an apparatus for transmitting light along multiple pathways.
  • the method generally includes positioning a plurality of large diameter optical waveguides, each having a core and a cladding, adjacent one another and fusing at least a portion of the cladding of each of the optical waveguides with the cladding of another one of the optical waveguides, such that the apparatus resulting therefrom is a monolithic structure.
  • Yet another embodiment of the present invention is an apparatus for transmitting light along multiple pathways.
  • the apparatus generally includes a plurality of large diameter optical waveguides, each having a core and a cladding, wherein the apparatus is a monolithic structure and wherein the core of a first one of the large diameter optical waveguides has a different structural parameter than the core of a second one of the large diameter optical waveguides.
  • Yet another embodiment of the present invention is a method for forming an apparatus for transmitting light along multiple pathways.
  • the method generally includes positioning a plurality of large diameter optical waveguides, each having a core and a cladding, in a plurality of bores of a body, wherein the core of a first one of the large diameter optical waveguides has a different structural parameter than the core of a second one of the large diameter optical waveguides; and fusing at least a portion of the cladding of each of the optical waveguides with the body, such that the apparatus resulting therefrom is a monolithic structure.
  • Yet another embodiment of the present invention is an optical waveguide feedthrough assembly.
  • the assembly generally includes a housing; an apparatus for transmitting light along multiple pathways, wherein the apparatus is at least partially disposed in the housing; and one or more annular sealing elements disposed between an inner surface of the housing and an outer surface of the apparatus.
  • the apparatus is a monolithic structure and includes a plurality of large diameter optical waveguides, each having a core and a cladding. The core of a first one of the large diameter optical waveguides has a different structural parameter than the core of a second one of the large diameter optical waveguides.
  • Yet another embodiment of the present invention is a method for forming an apparatus for transmitting light along multiple pathways.
  • the method generally includes positioning a plurality of large diameter optical waveguides, each having a core and a cladding, adjacent one another, wherein the core of a first one of the large diameter optical waveguides has a different structural parameter than the core of a second one of the large diameter optical waveguides; and fusing at least a portion of the cladding of each of the optical waveguides with the cladding of another one of the optical waveguides, such that the apparatus resulting therefrom is a monolithic structure.
  • Yet another embodiment of the present invention provides an apparatus for transmitting light along multiple pathways.
  • the apparatus generally includes a cladding and a plurality of cores disposed within the cladding, wherein a first one of the cores has a different refractive index property than a second one of the cores.
  • Yet another embodiment of the present invention provides an apparatus for transmitting light along multiple pathways.
  • the apparatus generally includes a cladding and a plurality of cores disposed within the cladding, wherein a first one of the cores has a different microstructure than a second one of the cores.
  • the apparatus generally includes a plurality of large diameter optical waveguides, each having a core and a cladding, wherein the apparatus is a monolithic structure and wherein the cores of the large diameter optical waveguides have the same structural parameters.
  • Figure 1 illustrates a cross-sectional view of a prior art optical waveguide feedthrough assembly.
  • Figure 2 is a diagram conceptually illustrating a monolithic multi-waveguide structure, according to an embodiment of the present invention.
  • Figure 3 is a diagram conceptually illustrating a monolithic multi-waveguide structure with a collapsed region and a larger outer diameter region, according to an embodiment of the present invention.
  • Figure 4 is a diagram conceptually illustrating a monolithic multi-waveguide structure disposed in a housing with annulus seals disposed therebetween, according to an embodiment of the present invention.
  • Figure 5 is a diagram conceptually illustrating two monolithic multi- waveguide connectors with locating features, according to an embodiment of the present invention.
  • Figure 6 is a diagram conceptually illustrating splicing of optical fibers to a monolithic multi-waveguide structure, according to an embodiment of the present invention.
  • Figures 7 and 8 are flow diagrams illustrating example operations for forming a monolithic structure for transmitting light along multiple pathways.
  • Figure 9A is a diagram conceptually illustrating a multi-core optical waveguide structure with all cores having the same core structure, according to an embodiment of the present invention.
  • Figure 9B is a diagram conceptually illustrating a multi-core optical waveguide structure with two different core structures, according to an embodiment of the present invention.
  • Embodiments of the present invention provide techniques and apparatus for a robust, reliable, high pressure optical waveguide feedthrough (penetrator) or connector that utilizes a monolithic glass structure.
  • the apparatus includes a plurality of large diameter optical waveguides, each having a core and a cladding, and a body having a plurality of bores with the optical waveguides disposed therein, wherein at least part of the cladding of each of the optical waveguides is fused with the body, such that the apparatus is a monolithic structure.
  • the apparatus includes a plurality of large diameter optical waveguides, each having a core and a cladding, wherein at least part of the cladding of each of the optical waveguides is fused with the cladding of another one of the optical waveguides, such that the apparatus is a monolithic structure.
  • monolithic structures supporting multiple optical waveguides are described in detail below. From this description, the ideas disclosed herein can be adapted to a capillary tube having only a single bore for supporting one optical waveguide.
  • optical fiber As used herein, “optical fiber,” “glass plug,” and the more general term “optical waveguide” refer to any of a number of different devices that are currently known or may later become known for transmitting optical signals along a desired pathway.
  • each of these terms can refer to single mode, multi-mode, birefringent, polarization-maintaining, polarizing, multi-core or multi-cladding optical waveguides, or flat or planar waveguides.
  • the optical waveguides may be made of any glass (e.g., silica, phosphate glass, or other glasses), of glass and plastic, or solely of plastic.
  • optical waveguides composed of a glass material are desirable.
  • any of the optical waveguides can be partially or completely coated with a gettering agent and/or a blocking agent (such as gold) to provide a hydrogen barrier that protects the waveguide.
  • FIG. 2 conceptually illustrates a monolithic structure 200 with multiple optical waveguides fused with multiple bores of a capillary tube 202.
  • Embodiments of the present invention such as the monolithic structure 200, may be used in place of the optical waveguide element 14 of Figure 1 .
  • the monolithic structure 200 includes a capillary tube 202 and a plurality of large-diameter optical waveguides 204, each waveguide having a core and a cladding. Before fusing, the capillary tube 202 had a plurality of bores running through the length of the capillary tube 202.
  • the tube 202 may include more or less than four bores, which may depend on the number of optical waveguides desired for a particular application.
  • the plurality of optical waveguides 204 are inserted into the bores.
  • a large-diameter optical waveguide also known as a cane waveguide
  • the capillary tube 202 has a larger outer diameter than the outer diameter of the large- diameter optical waveguides 204.
  • the capillary tube 202 is subjected to heat in one or more selected regions to fuse the capillary tube 202 and the optical waveguides 204 (at least within the collapsed region(s)). Typically performed with vacuum assist, this fusing collapses the bores of the capillary tube 202 around the cladding of the optical waveguides 204 to form a single monolithic structure.
  • the monolithic structure 200 is able to conduct light energy through multiple paths and effectively increases the outer diameter of the plurality of optical waveguides 204.
  • the capillary tube 202 and/or the core and cladding of each optical waveguide 204 are composed of silica glass, such as quartz.
  • the optical waveguides 204 may be 1 mm quartz cane waveguides for 1550 nm light.
  • the cladding of each optical waveguide 204 and capillary tube 202 have about the same temperature coefficient.
  • the capillary tube 202 may be a cylinder or have any of various other suitable shapes.
  • the capillary tube 202 may be made of quartz formed by drawing or drilling ⁇ e.g., multibore tubing offered by Friedrich & Dimmock, Inc. of Milleville, NJ).
  • the capillary tube 202 may be shaped by grinding, machining, or other means to form any feature of interest.
  • the capillary tube 202 may be shaped to form geometries important to sealing and stress reduction.
  • Figure 3 illustrates another monolithic structure 300, similar to the monolithic structure 200 of Figure 2, where the capillary tube 202 includes a collapsed region 306 (wherein fusing of the bores and optical waveguides 204 has occurred) and a shaped sealing region 308.
  • the sealing region 308 has a convex frustoconical shape.
  • the tapered ends of the convex frustoconical shaped sealing region 308 form sealing surfaces that are large compared to the outer diameter of the optical waveguides 204 and the collapsed region 306.
  • downhole pressure may be distributed on the monolithic structure 300 in a desired manner, with a surface reacting force acting on the sealing surface furthest away from the collapsed region.
  • the monolithic structure 200 may further include one or more annulus seals 410 ⁇ e.g., Accuseal, offered by Weatherford International with headquarters in Houston, TX) around the capillary tube 202 in collapsed region 306.
  • the annulus seals 410 may be any of various suitable sealing elements, such as v-ring seals, chevron seals, o-ring seals, gasket seals, etc.
  • the annulus seals 410 see internal pressure within a metal housing 412 corresponding to the outer diameter of the annulus seals 410.
  • the glass sees internal pressure within the metal housing corresponding to the smaller outer diameter of the capillary tube 202 in the collapsed region 306.
  • annulus seals 410 seal an annulus around the smaller diameter collapsed region 306, while sealing region 308 has a larger outer diameter and thus reacts to the axial force on the optical waveguide 204 over a much larger area (surface reacting force) which provides reduced stress on the glass.
  • the capillary tube 202 may be shaped to form geometries important to alignment of two monolithic multi-optical-waveguide connectors.
  • the capillary tube 202 may be shaped to include at least one locating feature 514.
  • the locating feature 514 is a flat (i.e., a flat surface) along a length of the capillary tube 202.
  • the flat is formed in an outer diameter of the capillary tube 202 and is parallel to an axis of the capillary tube 202.
  • the capillary tube 202 may be divided ⁇ e.g., by cutting or dicing) in the collapsed region 306 to form a connector pair.
  • the locating feature 514 allows the optical waveguides 204 to be realigned within the desired submicron alignment.
  • the parted capillary tube 202 may be realigned by butting the diced ends 512 against one another and using the flat (locating feature 514) to precisely align the outer diameter, thereby also aligning the optical waveguides 204. This is particularly useful for undersea wet connects.
  • the ends 512 of the cut portion may have a polished face.
  • the diced ends 512 may be aligned and connected using male/female connectors, where each end 512 is shaped to mate with the other end 512.
  • individual optical waveguides 204 may be spliced using a cone or carrier splice at 616, for example, with optical fibers 618.
  • carrier splicing for example, all but one of the carriers (which may be the optical waveguides 204) are pulled back, the remaining carrier is spliced, and this process is repeated for each carrier.
  • the carriers may be spliced using large diameter splicing (LDS) to the ends of the cane waveguides.
  • LDS large diameter splicing
  • FIG. 7 is a flow diagram illustrating example operations 700 for forming an apparatus for transmitting light along multiple pathways.
  • the operations 700 begin, at 702, by positioning a plurality of large diameter optical waveguides ⁇ e.g., waveguides 204), each having a core and a cladding, in a plurality of bores of a body ⁇ e.g., the cylindrical capillary tube 202 of Figure 2).
  • the bores may be drilled in the body prior to positioning the optical waveguides in the bores.
  • the body having the plurality of bores may be drawn from a preform having a plurality of bores.
  • At 704 at least a portion of the cladding of each of the optical waveguides is fused with the body, such that the apparatus resulting therefrom is a monolithic structure ⁇ e.g., structure 200).
  • at least one orientation feature may be formed in the body before the fusing at 704 or in the apparatus after the fusing.
  • the apparatus may be diced in the fused portion to form two apparatuses.
  • Each of the two apparatuses may be a monolithic structure ⁇ e.g., if the dicing occurs in the collapsed region 306).
  • an end face of at least one of the two apparatuses may be polished at 707.
  • at least one orientation feature may be formed in the two apparatuses ⁇ e.g., in the end faces 512 of the two apparatuses).
  • the end faces of the two apparatuses may be butted together, such that the optical waveguides in the two apparatuses are aligned.
  • the optical waveguides may be aligned using at least one orientation feature (e.g., locating feature 514) in at least one of the two apparatuses.
  • the orientation feature may be at least one flat surface formed in an outer diameter of the body and parallel to an axis of the body.
  • a plurality of optical fibers e.g., fibers 618) may be spliced (e.g., at 616) to the plurality of large diameter optical waveguides.
  • the splicing may involve cone splicing or carrier splicing.
  • a monolithic structure as described above may be formed without using a body (e.g., a capillary tube).
  • Figure 8 is a flow diagram illustrating example operations 800 for forming an apparatus for transmitting light along multiple pathways by fusing the claddings of multiple large diameter optical waveguides together.
  • the operations 800 may begin, at 802, by positioning a plurality of large diameter optical waveguides (e.g., waveguides 204), each having a core and a cladding, adjacent one another (e.g., in a bundle).
  • At 804 at least a portion of the cladding of each of the optical waveguides is fused with the cladding of another one of the optical waveguides, such that the apparatus resulting therefrom is a monolithic structure.
  • This fusing may be performed in the same region on each of the optical waveguides, such that the monolithic structure may be used as an optical feedthrough.
  • Many of the operations 700 of Figure 7 described above may also be performed for the monolithic structure formed according to the operations 800 of Figure 8.
  • the apparatus may be diced in the fused portion to form two apparatuses, which may be polished and later butted together (e.g., using one or more orientation features for alignment).
  • FIMT fiber-in-metal-tube
  • DTS distributed temperature sensing
  • these fibers may be multi-mode or single-mode optical fibers, although multi-mode fibers are typically preferred.
  • Other optical sensing products for sensing pressure, temperature, seismic properties, or flow, for example
  • Embodiments of the present invention provide multi-core optical waveguides where the cores possess different structural properties. These properties may include any combination of different sizes, transverse shapes, refractive index properties (e.g., different refractive index values and/or graded versus stepped refractive index cores), microstructures (e.g., photonic-crystal fiber (PCF) using hollow cores versus solid cores), and the like.
  • refractive index properties e.g., different refractive index values and/or graded versus stepped refractive index cores
  • microstructures e.g., photonic-crystal fiber (PCF) using hollow cores versus solid cores
  • Figure 9A conceptually illustrates an example multi-core optical waveguide structure 900, which may be similar to the monolithic structure 200 in Figure 2.
  • the claddings of the large-diameter waveguides fuse with the collapsed walls of the bores to form the fused cladding region 904 of the structure 900, as described above.
  • four cores 902 are shown in Figure 9A as an example, the structure 900 may include more or less than four cores, which may depend on the number of optical pathways desired for a particular application.
  • the structure 900 of Figure 9A may be similar to the monolithic structure 200 in Figure 2, the structure 900 may also represent an optical fiber, a cane waveguide, an optical sensor, an optical feedthrough, or an optical connector having multiples cores 902 disposed in a cladding region 904.
  • the cores 902 all have the same core structure, meaning that the structural parameters (e.g., size and shape) of the cores are all the same.
  • all four cores 902 are solid cores having a circular transverse shape and the same diameter di .
  • the cores 902 may function as either all single-mode or all multimode cores.
  • FIG. 9B conceptually illustrates an example multi-core optical waveguide structure 910 with two different core structures, which may also be similar to the monolithic structure 200 in Figure 2 such that the description above applies to Figure 9B, as well.
  • cores 902 have the same core structure (e.g., diameter di).
  • cores 912 have a different core structure, such as the larger diameter 02 as shown. In this manner, the smaller diameter cores 902 of the multi-core structure 910 may function as single-mode cores, whereas the larger diameter cores 912 may function as multimode cores.
  • the smaller diameter cores 902 may be used for a different application (e.g., Bragg grating sensing or distributed acoustic sensing (DAS)) than the large diameter cores 912 (e.g., distributed temperature sensing (DTS)).
  • DAS distributed acoustic sensing
  • DTS distributed temperature sensing
  • the cores of a multi-core optical waveguide may differ with respect to other structural parameters, such as different transverse shapes, different refractive index properties, and/or different microstructures.
  • one core may have a circular cross-section, whereas another core may have an elliptical, rectangular, or annular cross-section.
  • one core may have a greater refractive index value than another core of the same multi-core optical waveguide structure.
  • one core may have a stepped refractive index with respect to the cladding (i.e., the core has a single refractive index value throughout, that is distinct from the cladding's refractive index, such that a graph of refractive index versus diameter would form a step between this core and the cladding), while another core may have a graded refractive index (i.e., two or more different refractive index values, whether a piecewise or a continuous function).
  • one core may be a solid core, whereas another core may be a photonic-crystal fiber (PCF) core, which may guide light through the optical waveguide using the internal structure of the waveguide, rather than only using refractive index differences.
  • PCF photonic-crystal fiber
  • one type of PCF known as "holey fiber" uses hollow cores, which may be filled with air.
  • Permitting different core structures within the same optical waveguide structure may provide for easier design of feedthroughs, pass-throughs, connectors, cable structures, and the like, especially when it is desirable to include both single- mode and multimode capabilities in a single device (e.g., for space constraints).
  • Embodiments of the invention heretofore can be used and have specific utility in applications within the oil and gas industry. Further, it is within the scope of the invention that other commercial embodiments/uses exist with one such universal sealing arrangement shown in the figures and adaptable for use in (by way of example and not limitation) industrial, chemical, energy, nuclear, structural, etc. While the foregoing is directed to preferred embodiments of the invention, other and further embodiments of the invention may be devised without departing from the basic scope thereof, and the scope thereof is determined by the claims that follow.

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Optics & Photonics (AREA)
  • Optical Couplings Of Light Guides (AREA)

Abstract

L'invention concerne des procédés et un appareil permettant de transmettre la lumière le long de multiples chemins à l'aide d'un dispositif optique multi-cœur. Un appareil donné à titre d'exemple comprend, en règle générale, une pluralité de guides d'ondes optiques de grand diamètre comportant chacun un cœur et une gaine, et un corps comportant une pluralité d'alésages, les guides d'ondes optiques étant disposés dans ces derniers, au moins une partie de la gaine de chaque guide d'ondes optiques étant fusionnée avec le corps de telle sorte que l'appareil présente une structure monolithique. Un tel appareil permet d'obtenir une technique économique et à encombrement réduit pour l'orifice d'amenée des multiples guides d'ondes optiques. De même, le corps peut présenter un grand diamètre externe qui peut être formé dans des caractéristiques dignes d'intérêt, telles que des caractéristiques d'alignement de connexion ou d'étanchéité d'orifice d'amenée. Selon certains modes de réalisation, au moins quelques cœurs peuvent présenter différents paramètres de structure (par exemple, la taille et/ou la forme).
PCT/US2014/065417 2013-11-15 2014-11-13 Guide d'ondes optiques multi-cœur pour une détection de multiples paramètres WO2015126479A1 (fr)

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US14/081,045 2013-11-15
US14/081,045 US20140241681A1 (en) 2013-02-22 2013-11-15 Multi-core optical waveguide for multi-parameter sensing

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EP0601558A1 (fr) * 1992-12-08 1994-06-15 SEIKOH GIKEN Co., Ltd. Démultiplexeur/multiplexeur optique
GB2341014A (en) * 1998-06-23 2000-03-01 Pirelli Cables Sa A seal to surround a cable on entry to a junction box
US20070003206A1 (en) 2005-06-30 2007-01-04 Dunphy James R Optical waveguide feedthrough assembly
US20080145015A1 (en) * 2006-11-01 2008-06-19 Dunphy James R Optical waveguide feedthrough assembly

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CA2441918C (fr) * 2003-09-19 2010-06-08 Itf Technologies Optiques Inc./Itf Optical Technologies Inc. Coupleur optique comprenant des fibres multimodes et methode de fabrication de ce coupleur
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ATE483997T1 (de) * 2006-03-17 2010-10-15 Nkt Photonics As Optischer koppler und verfahren zu seiner herstellung und verwendung
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WO2011052373A1 (fr) * 2009-10-27 2011-05-05 株式会社フジクラ Mélangeur de lumière et dispositif de laser à fibre l'utilisant

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Publication number Priority date Publication date Assignee Title
EP0601558A1 (fr) * 1992-12-08 1994-06-15 SEIKOH GIKEN Co., Ltd. Démultiplexeur/multiplexeur optique
GB2341014A (en) * 1998-06-23 2000-03-01 Pirelli Cables Sa A seal to surround a cable on entry to a junction box
US20070003206A1 (en) 2005-06-30 2007-01-04 Dunphy James R Optical waveguide feedthrough assembly
US20080145015A1 (en) * 2006-11-01 2008-06-19 Dunphy James R Optical waveguide feedthrough assembly

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GB2557492B (en) 2018-08-01
GB2557492A (en) 2018-06-20
GB2535049A (en) 2016-08-10
GB2535049B (en) 2018-07-18
GB201802460D0 (en) 2018-04-04

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