US4997247A — Fiber optic coupler and method for making same

Claim 1

Independent Claim 147 words

A fiber optic coupler comprising at least two optical fibers each having a core with a cladding material disposed thereabout, said fibers in a limited length coupling region having the cladding material fully removed, the core fully exposed and at least 4% of the outer diameter of the core of at least one of said fibers removed in said coupling region, such that the core diameter in the coupling region is less than the core diameter in regions adjacent thereto, the outer diameter of said core decreasing in smooth transition from immediately adjacent the cladding material, and the thickness of the cladding material increasing in smooth transition from immediately adjacent the exposed core in the limited length coupling region, said fibers in said limited length coupling region extended along the sides of each other in crossed relationship, having a constant azimuthal angle and being joined by coalescing.

Claim 2

Dependent Claim 147 words

A fiber optic coupler comprising at least two optical fibers each having a core with a cladding material disposed thereabout, said fibers in a limited length coupling region having the cladding material fully removed, the core fully exposed and at least 4% of the outer diameter of the core of at least one of said fibers removed in said coupling region, such that the core diameter in the coupling region is less than the core diameter in regions adjacent thereto, the outer diameter of said core decreasing in smooth transition from immediately adjacent the cladding material, and the thickness of the cladding material increasing in smooth transition from immediately adjacent the exposed core in the limited length coupling region, said fibers in said limited length coupling region extended along the sides of each other in crossed relationship, having a constant azimuthal angle and being joined by coalescing.

Claim 3

Dependent Claim 24 words

The fiber optic coupler of claim 1 wherein the material of said core of at least one of said fibers is removed by etching.

Claim 4

Dependent Claim 15 words

The fiber optic coupler of claim 1 wherein said cladding material is removed by etching.

Claim 5

Dependent Claim 16 words

The fiber optic coupler of claim 1 wherein said cladding material is removed by solvent action.

Claim 6

Dependent Claim 26 words

The fiber optic coupler of claim 1 in the form of star coupler comprising a plurality of optical fibers joined at said limited length coupling region.

Claim 7

Dependent Claim 103 words

A fiber optic coupler in the form of star coupler comprising a plurality of optical fibers each having a core with a cladding material disposed thereabout, said fibers in a limited length coupling region having the cladding material removed and the core exposed, the thickness of the cladding material increasing in smooth transition from immediately adjacent the exposed core in the limited length coupling region, said fibers in said limited length coupling region being joined by coalescing and wherein, in said limited length coupling region, the joined fibers are necked down abruptly in a manner to cause light transmitted therethrough to be randomized.

Claim 8

Dependent Claim 103 words

A fiber optic coupler in the form of star coupler comprising a plurality of optical fibers each having a core with a cladding material disposed thereabout, said fibers in a limited length coupling region having the cladding material removed and the core exposed, the thickness of the cladding material increasing in smooth transition from immediately adjacent the exposed core in the limited length coupling region, said fibers in said limited length coupling region being joined by coalescing and wherein, in said limited length coupling region, the joined fibers are necked down abruptly in a manner to cause light transmitted therethrough to be randomized.

Claim 9

Dependent Claim 116 words

A fiber optic coupler comprising at least two optical fibers each having a core with a cladding material disposed thereabout, said fibers in a limited length coupling region having the cladding material removed by etching and the core substantially exposed, wherein, prior to removal of said cladding material, said core and cladding material of at least one fiber is biconically pre-tapered by drawing, the thickness of the cladding material of said fiber, as a result of etching the cladding of the pre-tapered fiber, increasing in smooth transition from immediately adjacent the exposed core in the limited length coupling region, said substantially exposed cores of said fibers in said limited length coupling region being joined by coalescing.

Claim 10

Dependent Claim 116 words

A fiber optic coupler comprising at least two optical fibers each having a core with a cladding material disposed thereabout, said fibers in a limited length coupling region having the cladding material removed by etching and the core substantially exposed, wherein, prior to removal of said cladding material, said core and cladding material of at least one fiber is biconically pre-tapered by drawing, the thickness of the cladding material of said fiber, as a result of etching the cladding of the pre-tapered fiber, increasing in smooth transition from immediately adjacent the exposed core in the limited length coupling region, said substantially exposed cores of said fibers in said limited length coupling region being joined by coalescing.

Claim 11

Dependent Claim 30 words

The fiber optic coupler of claim 1 wherein at least one of said coupled fibers has a biconical tapered region created by drawing the respective ends of the fibers apart.

Claim 12

Dependent Claim 19 words

The fiber optic coupler of claim 1 or 8 wherein a plurality of said fibers are joined by braiding.

Claim 13

Dependent Claim 109 words

A multimode fiber optic coupler, said coupler comprising at least two optical fibers each having a core with a cladding material disposed thereabout, said fibers in a limited length region having the cladding material removed and the core substantially exposed, the thickness of the cladding material increasing in smooth transition from immediately adjacent the substantially exposed core in the limited length region, the cores of said fibers in said limited length region extending generally lengthwise and substantially symmetrically along the sides of each other in crossed relationship, each fiber having a constant azimuthal angle, and being joined by coalescing to provide effective coupling of light in a coupling region.

Claim 14

Dependent Claim 109 words

A multimode fiber optic coupler, said coupler comprising at least two optical fibers each having a core with a cladding material disposed thereabout, said fibers in a limited length region having the cladding material removed and the core substantially exposed, the thickness of the cladding material increasing in smooth transition from immediately adjacent the substantially exposed core in the limited length region, the cores of said fibers in said limited length region extending generally lengthwise and substantially symmetrically along the sides of each other in crossed relationship, each fiber having a constant azimuthal angle, and being joined by coalescing to provide effective coupling of light in a coupling region.

Claim 15

Dependent Claim 108 words

A multimode fiber optic coupler comprising at least two optical fibers each having a core with a cladding material disposed thereabout, said fibers in a limited length region having the cladding material removed and the core substantially exposed, the thickness of the cladding material increasing in smooth transition from immediately adjacent the substantially exposed core int eh limited length region, the core of said fibers in said limited length region extending generally lengthwise and substantially symmetrically along the sides of each other in crossed relationship and being joined by coalescing to provide effective coupling of light, and wherein the fibers joined in said region have no stored torsion.

Claim 16

Dependent Claim 108 words

A multimode fiber optic coupler comprising at least two optical fibers each having a core with a cladding material disposed thereabout, said fibers in a limited length region having the cladding material removed and the core substantially exposed, the thickness of the cladding material increasing in smooth transition from immediately adjacent the substantially exposed core int eh limited length region, the core of said fibers in said limited length region extending generally lengthwise and substantially symmetrically along the sides of each other in crossed relationship and being joined by coalescing to provide effective coupling of light, and wherein the fibers joined in said region have no stored torsion.

Claim 17

Independent Claim 161 words

A method for forming a fiber optic coupler comprising: providing at least two optical fibers each having a core with a cladding material disposed thereabout; in a limited length coupling region of each fiber, removing the cladding material to fully expose said core in a manner whereby the cladding material immediately adjacent the exposed core increases in thickness in smooth transition; removing, in the limited length coupling region, a portion of the core in a manner whereby the outer diameter of said core decreases in smooth transition from immediately adjacent the cladding material, said step including removing at least 4% of the outer diameter of the core of at least one of said fibers in said coupling regions arranging the fibers along side each other in crossed relationship with a constant azimuthal angle; and joining the exposed ores of said optical fibers in the limited length region by coalescing whereby light transmitted through said fibers is coupled in the coalesced region.

Claim 18

Independent Claim 161 words

A method for forming a fiber optic coupler comprising: providing at least two optical fibers each having a core with a cladding material disposed thereabout; in a limited length coupling region of each fiber, removing the cladding material to fully expose said core in a manner whereby the cladding material immediately adjacent the exposed core increases in thickness in smooth transition; removing, in the limited length coupling region, a portion of the core in a manner whereby the outer diameter of said core decreases in smooth transition from immediately adjacent the cladding material, said step including removing at least 4% of the outer diameter of the core of at least one of said fibers in said coupling regions arranging the fibers along side each other in crossed relationship with a constant azimuthal angle; and joining the exposed ores of said optical fibers in the limited length region by coalescing whereby light transmitted through said fibers is coupled in the coalesced region.

Claim 19

Dependent Claim 21 words

The method of claim 12 comprising removing the material of said core of at lest one of said fibers by etching.

Claim 20

Dependent Claim 12 words

The method of claim 12 comprising removing said cladding material by etching.

Claim 21

Dependent Claim 13 words

The method of claim 12 comprising removing said cladding material by solvent action.

Claim 22

Independent Claim 110 words

A method for formation of a a star coupler comprising providing a plurality of optical fibers each having a core with a cladding material disposed thereabout; in a limited length region of each fiber, removing the cladding material to expose said core in a manner whereby the cladding material immediately adjacent the exposed core increases in thickness in smooth transition; joining the exposed cores of said optical fibers in the limited length region by coalescing whereby light transmitted through said fibers is coupled in the coalesced region; and in said limited length coupling region, necking down the fibers abruptly in a manner to cause light transmitted therethrough to be randomized.

Claim 23

Independent Claim 110 words

A method for formation of a a star coupler comprising providing a plurality of optical fibers each having a core with a cladding material disposed thereabout; in a limited length region of each fiber, removing the cladding material to expose said core in a manner whereby the cladding material immediately adjacent the exposed core increases in thickness in smooth transition; joining the exposed cores of said optical fibers in the limited length region by coalescing whereby light transmitted through said fibers is coupled in the coalesced region; and in said limited length coupling region, necking down the fibers abruptly in a manner to cause light transmitted therethrough to be randomized.

Claim 24

Independent Claim 132 words

A method for forming a multimode fiber optic coupler comprising: providing at least two optical fibers each having a core with a cladding material disposed thereabout; drawing said core and cladding material of at least one said fiber into a biconical taper; thereafter, in a limited length region of each fiber, removing the cladding material to substantially expose said core in a manner whereby the cladding material immediately adjacent the substantially exposed core increases in thickness in smooth transition; arranging the substantially exposed cores of said fibers to extend generally lengthwise and substantially symmetrically along the sides of each other in crossed relationship; joining the substantially exposed cores of said optical fibers in the limited length region by coalescing whereby light transmitted through said fibers is coupled effectively int he coalesced region.

Claim 25

Independent Claim 132 words

A method for forming a multimode fiber optic coupler comprising: providing at least two optical fibers each having a core with a cladding material disposed thereabout; drawing said core and cladding material of at least one said fiber into a biconical taper; thereafter, in a limited length region of each fiber, removing the cladding material to substantially expose said core in a manner whereby the cladding material immediately adjacent the substantially exposed core increases in thickness in smooth transition; arranging the substantially exposed cores of said fibers to extend generally lengthwise and substantially symmetrically along the sides of each other in crossed relationship; joining the substantially exposed cores of said optical fibers in the limited length region by coalescing whereby light transmitted through said fibers is coupled effectively int he coalesced region.

Claim 26

Independent Claim 103 words

The method of forming an optical coupler comprising: a. mounting a first fiber in a first fixture in a manner to at least minimize torsional rotation of the first fiber and thus ensure said first fiber is in neutral condition, b. arranging a second fiber to lie in intimate cross contact with said first fiber in a coupling region, said second fiber so arranged in a manner to at least minimize torsional rotation of the second fiber and thus ensure said second fiber is in neutral condition; and c. with said fibers taut, applying heat to said coupling region to fuse said fibers.

Claim 27

Independent Claim 103 words

The method of forming an optical coupler comprising: a. mounting a first fiber in a first fixture in a manner to at least minimize torsional rotation of the first fiber and thus ensure said first fiber is in neutral condition, b. arranging a second fiber to lie in intimate cross contact with said first fiber in a coupling region, said second fiber so arranged in a manner to at least minimize torsional rotation of the second fiber and thus ensure said second fiber is in neutral condition; and c. with said fibers taut, applying heat to said coupling region to fuse said fibers.

Claim 28

Dependent Claim 56 words

The method of claim 18 wherein said second fiber is mounted in a second fixture and said method comprises the further step of inverting said second fixture holding the second fiber onto the fixture holding the first fiber, with the fixtures in registration to cause the fibers to lie in intimate contact in a coupling region.

Claim 29

Dependent Claim 28 words

The method of claim 18 or 19 wherein during fusing of said fibers the respective ends of the fibers are drawn apart to create a biconical tapered region.

Claim 30

Dependent Claim 16 words

The method of claim 18 or 19 wherein a plurality of fibers are joined by braiding.

Claim 31

Dependent Claim 82 words

A fiber optic coupler comprising: at least two optical fibers each having a core with a cladding material disposed thereabout, said fibers in a limited length coupling region having the cladding material removed and the core exposed, the thickness of the cladding material increasing in smooth transition from immediately adjacent the exposed core; said fibers crossing one another in a manner so as to maintain a constant azimuthal angle within each fiber; and said fibers joined in said coupling region by coalescing.

Claim 32

Dependent Claim 82 words

A fiber optic coupler comprising: at least two optical fibers each having a core with a cladding material disposed thereabout, said fibers in a limited length coupling region having the cladding material removed and the core exposed, the thickness of the cladding material increasing in smooth transition from immediately adjacent the exposed core; said fibers crossing one another in a manner so as to maintain a constant azimuthal angle within each fiber; and said fibers joined in said coupling region by coalescing.

Claim 33

Dependent Claim 78 words

A fiber optic coupler comprising: at least two optical fibers each having a core with a cladding material disposed thereabout, said fibers in a limited length coupling region having the cladding material removed and the core exposed, the thickness of the cladding material increasing in smooth transition from immediately adjacent the exposed core; said fibers crossing one another in a manner so as to not store an tension and; said fibers joined in said coupling region by coalescing.

Claim 34

Dependent Claim 78 words

A fiber optic coupler comprising: at least two optical fibers each having a core with a cladding material disposed thereabout, said fibers in a limited length coupling region having the cladding material removed and the core exposed, the thickness of the cladding material increasing in smooth transition from immediately adjacent the exposed core; said fibers crossing one another in a manner so as to not store an tension and; said fibers joined in said coupling region by coalescing.

Claim 35

Dependent Claim 16 words

The fiber optic coupler of claim 1 formed by fusing and drawing said fibers during coalescing.

Claim 36

Dependent Claim 23 words

The fiber optic coupler of claim 7 wherein each of said fibers is biconically tapered by drawing prior to removal of said cladding.

Annuity Stage	Window Opens	Payment Deadline	Surcharge Period Until	Estimated Fee	Status
3.5 Years (Year 4)	1994-03-04	1994-09-03	1995-03-05	$2000.00	Window Closed / Lapsed
7.5 Years (Year 8)	1998-03-04	1998-09-03	1999-03-05	$3760.00	Window Closed / Lapsed
11.5 Years (Year 12)	2002-03-04	2002-09-03	2003-03-05	$7700.00	Window Closed / Lapsed

Fiber optic coupler and method for making same

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