Patent US6628947B1 successfully refreshed from Google Patents.
EP0212954A2
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EP
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Method of making low loss fiber optic coupler
Assignee: Corning Glass Works
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Filing: 1986-08-15
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Granted: —
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Expires: 2006-08-15
Abstract
Abstract A low loss fiber optic coupler is fabricated by forming a coupler preform (10) having a plurality of spaced glass cores (12,13) extending longitudinally through a matrix of glass having a refractive index lower than that of the cores. The preform is heated and stretched to form a glass rod (20) which is then severed into a plurality of units (21). Heat is applied to the central region (23) of each unit while the ends of the unit are pulled apart to elongate the taper inwardly the heated central region. The unit is then provided with a plurality of optical fibers (69, 70, 75, 76°, 82, 83; 89), one of which extends from each of the cores at the endfaces of the unit. A preferred method of providing the optical fibers involves forming the coupler preform of a matrix glass (46) that is easily dissolves in a solvent. Each of the fiber cores within the matrix is surrounded by a layer of cladding glass (54) that is relatively resistant to disolving by the solvent.
Inventors
- 👤 Donald Bruce Keck
- 👤 Donald Ray Lyons
- 👤 Daniel Aloysius Nolan
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-06 19:59
CPC Classifications
G; G02; G02B; G02B6/00; G02B6/24; G02B6/26; G02B6/28; G02B6/2804; G02B6/2817; C; C03; C03B; C03B23/00; C03B23/04; C03B23/047; C03B23/0473; C03B37/00; C03B37/01; C03B37/012; C03B37/01205; C03B37/014; C03B37/01466; C03B37/02; C03B37/025; C03B37/028; G02B6/2808; G02B6/2821; G02B6/2835; G02B6/2843; C03B2203/00; C03B2203/02; C03B2203/30; C03B2203/34
Claims Analysis
Total Claims: 23
Claim 1
Independent Claim
131 words
A method of fabricating a fiber optic coupler comprising the steps of forming a coupler preform having a plurality of spaced glass cores extending longitudinally through a matrix of glass having a refractive index lower than that of said glass cores, heating and stretching said preform to form a glass rod, severing said rod into a plurality of units in which the cores are flush with the endfaces thereof, applying heat to the central region of each of said units, and pulling one end of each of said units relative to the other to elongate and taper inwardly the heated central region thereof, whereby the cores of said unit are more closely spaced and are of smaller diameter at said central region than they are at the ends of said unit.
Claim 2
Independent Claim
131 words
A method of fabricating a fiber optic coupler comprising the steps of forming a coupler preform having a plurality of spaced glass cores extending longitudinally through a matrix of glass having a refractive index lower than that of said glass cores, heating and stretching said preform to form a glass rod, severing said rod into a plurality of units in which the cores are flush with the endfaces thereof, applying heat to the central region of each of said units, and pulling one end of each of said units relative to the other to elongate and taper inwardly the heated central region thereof, whereby the cores of said unit are more closely spaced and are of smaller diameter at said central region than they are at the ends of said unit.
Claim 3
Dependent Claim
59 words
A method in accordance with claim 1 wherein the steps of applying heat and pulling comprise the steps of providing a heated zone, providing relative movement between said heated zone and said unit, and applying to said unit a tensile force the magnitude of which depends upon the relative position of said unit with respect to said heated zone.
Claim 4
Dependent Claim
58 words
A method in accordance with claim 2 wherein, during the steps of applying heat and pulling, said heated zone is stationary and said method comprises moving one end of said unit away from said heated zone and moving the remaining end of said unit in the same direction as said one end but at a lower instantaneous velocity.
Claim 5
Dependent Claim
21 words
A method in accordance with claim 3 wherein the velocity of movement of the remaining end of said unit is constant.
Claim 6
Dependent Claim
48 words
A method in accordance with claim 4 wherein the velocity of movement of said one end of said unit gradually increases during the formation of a transition region, remains constant during the formation of a coupling region, and gradually decreases during the formation of a second transition region.
Claim 7
Independent Claim
43 words
A method in accordance with any preceding claim wherein the step of pulling comprises an amount sufficient to reduce the diameters of said cores to a value no smaller than about 1/20 the diameter of said cores at the ends of said unit.
Claim 8
Independent Claim
102 words
A method in accordance with any preceding claim wherein the step of forming a coupler preform comprises forming a preform having a plurality of spaced glass cores extending through a matrix of glass produced by a chemical vapor deposition process which results in refractive index striae the thickness of which is greater than λ, wherein X is the wavelength of light to be propagated by said coupler, and wherein the step of heating and stretching comprises stretching said coupler preform an amount sufficient to reduce the diameter thereof such that the radius of each of said striae is no greater than X.
Claim 9
Independent Claim
43 words
A method in accordance with any preceding claim further comprising the step of providing a plurality of optical fibers, said optical fibers extending from at least one of the endfaces of said coupler in alignment with each of the coupler cores extending thereto.
Claim 10
Dependent Claim
47 words
A method in accordance with claim 8 wherein each of said coupler cores terminates at said endfaces, and wherein the step of providing a plurality of optical fibers comprises bonding one of said optical fibers to the point at which a coupler core termintes at an endface.
Claim 11
Dependent Claim
83 words
A method in accordance with claim 8 wherein the cores of said coupler terminate at the endfaces thereof and wherein the step of providing a plurality of optical fibers comprises affixing a termintion cap to at least end of said coupler, said cap having a plurality of holes, one of said holes being in alignment with a respective one of the coupler cores terminating at that endface, and inserting one of said optical fibers into each of the holes of said termiation cap.
Claim 12
Dependent Claim
135 words
A method in accordance with claim 8 wherein said matrix glass is relatively easily dissolved in a given solvent, wherein each of said coupler cores is surrounded by a layer- of cladding glass that is relatively resistant to being dissolved in said given solvent and wherein the step of providing a plurality of optical fibers comprises immersing at least one end of said unit in a bath of said given solvent to dissolve the immersed region of said matrix glass from the end of said unit to thereby expose the ends of said unit cores and the surrounding layer of solvent-resistant cladding glass, the undissolved matrix glass at the end of said unit constituting an endface, each of said cores and surrounding layer of undissolved cladding glass constituting a fiber that protrudes from said endface.
Claim 13
Dependent Claim
55 words
A method in accordance with claim 11 wherein the step of immersing comprises immersing at least one of said ends of said unit to a given depth in said bath and partially withdrawing said unit from said bath during the dissolving of said matrix glass to form a tapered endface and strengthen said protruding fibers.
Claim 14
Dependent Claim
100 words
A method in accordance with claim 1 wherein said matrix glass is relatively easily dissolved in a given solvent and wherein each of said coupler cores is surrounded by a layer of cladding glass that is relatively resistant to being dissolved in said given solvent, said method further comprising immersing one end of said unit in a bath of said given solvent to dissolve the immersed region of matrix glass to thereby expose the ends of said unit cores and the surrounding layer of solvent resistant glass and applying a light reflective coating to the remaining end of said unit.
Claim 15
Dependent Claim
136 words
A method in accordance with claim 1 wherein the step of ferming a coupler preforrr comprises providing an elonganed boule of matrix glass that is relatively easily dissolved in a given solvent, forming a plurality of longitudinally extending holes in said boule, providing a plurality of fiber preforms comprising an axial region of said core glass surrounded by a layer of cladding glass that is relatively resistant to dissolving in said solvent, and inserting one of said fiber preforms into each of said holes, said method further comprising, after the step of pulling, the step of immersing an end of said unit into a bath of said solvent to dissolve the immersed region of matrix glass, the unit cores and surrounding layers of solvent resistant cladding glass thereby extending from the remaining mass of matrix glass.
Claim 16
Dependent Claim
123 words
A low loss fiber optic coupler comprising an elongated body of matrix glass, said body having two endfaces, said matrix glass being relatively easily dissolved in a given solvent, a plurality of optical fibers extending longitudinally through said body and protruding from at least one endface thereof, said fibers having at least a core and an outer layer of cladding glass that is more resistant to being dissolved in said given solvent than said matrix glass, the diameters of the central region of said elongated body and of said optical fibers in said central region being smaller than the diameters thererof at the endfaces of said body and said optical fibers being more closely spaced at sa.id central region than at said endfaces.
Claim 17
Dependent Claim
123 words
A low loss fiber optic coupler comprising an elongated body of matrix glass, said body having two endfaces, said matrix glass being relatively easily dissolved in a given solvent, a plurality of optical fibers extending longitudinally through said body and protruding from at least one endface thereof, said fibers having at least a core and an outer layer of cladding glass that is more resistant to being dissolved in said given solvent than said matrix glass, the diameters of the central region of said elongated body and of said optical fibers in said central region being smaller than the diameters thererof at the endfaces of said body and said optical fibers being more closely spaced at sa.id central region than at said endfaces.
Claim 18
Dependent Claim
33 words
A fiber optic coupler in accordance with claim 15 wherein the refractive index of said matrix glass is substantially the same as or less than that of said fiber optic outer cladding glass.
Claim 19
Dependent Claim
24 words
A fiber optic coupler in accordance with claim 15 or 16 wheiein a plurality of optical fibers extend from both ends of said body.
Claim 20
Dependent Claim
34 words
A fiber optic coupler in accordance with claim 15 or 16 wherein a plurality of optical fibers extend from only one of said body, the remaining end of said body having a reflective endface.
Claim 21
Dependent Claim
45 words
A fiber optic coupler in accordance with any of claims 15 to 18 wherein that endface from which said fibers protrude is tapered such that said unit is shortest at the periphery of said endface and more elongated axially in the vicinity of said fibers.
Claim 22
Dependent Claim
40 words
A fiber optic coupler in accordance with any of claims 15 to 19 wherein the diameters of said cores in the central region of said body are no smaller than 1/20 the diameter thereof at the endfaces of said body.
Claim 23
Dependent Claim
25 words
A fiber optic coupler in accordance with any of claims i5 to 20 wherein said optical fibers protrude at least 1 em from said endfaces.
References Cited (Backward Citations)
No citation records indexed.
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