US5016963A — Fiber optic coupler and method of making same

Claim 1

Independent Claim 102 words

A 1×N fiber optic coupler comprising a GRIN lens having first and second opposite sides; a first optical fiber having a microlens formed at a first end, said first end of said optical fiber fixed in relation to said GRIN lens at said first side; and a plurality of N second optical fibers, each of said second fibers having a tapered end section, said second optical fiber tapered end sections fixed in a bundle at said second side of said GRIN lens; whereby a light signal from said first optical fiber is split into N light signals in said second optical fibers.

Claim 2

Dependent Claim 102 words

A 1×N fiber optic coupler comprising a GRIN lens having first and second opposite sides; a first optical fiber having a microlens formed at a first end, said first end of said optical fiber fixed in relation to said GRIN lens at said first side; and a plurality of N second optical fibers, each of said second fibers having a tapered end section, said second optical fiber tapered end sections fixed in a bundle at said second side of said GRIN lens; whereby a light signal from said first optical fiber is split into N light signals in said second optical fibers.

Claim 3

Dependent Claim 36 words

The fiber optic coupler as in claim 2 wherein said first optic fiber and said bundle of said second optic fiber end sections are fixed along and aligned with the optical axis of said GRIN lens.

Claim 4

Dependent Claim 34 words

The fiber optic coupler as in claim 2 further comprising a material between said tapered ends of said second optic fibers, said material having an index of refraction less than that of said fibers.

Claim 5

Dependent Claim 22 words

The fiber optic coupler as in claim 3 wherein said material is an adhesive binding said second optic fibers into said bundle.

Claim 6

Dependent Claim 23 words

The fiber optic coupler as in claim 2 further comprising a ferrule enclosing said bundle of tapered end sections of second optical fibers.

Claim 7

Dependent Claim 33 words

The fiber optic coupler as in claim 5 wherein said bundle is fixed in said ferrule by epoxy, said epoxy having an index of refraction less than that of said second optic fibers.

Claim 8

Dependent Claim 37 words

The fiber optic coupler as in claim 2 wherein said tapered end sections of said second optic fibers have ends perpendicular to said second optic fibers, said tips fixed against said second side of said GRIN lens.

Claim 9

Dependent Claim 52 words

The fiber optic coupler as in claim 7 wherein said ends of said second optic fibers cover a limited area around said GRIN lens optical axis so that the falloff in light intensity from said optical axis of light signals transmitted from said first optic fiber through said GRIN lens is limited.

Claim 10

Dependent Claim 20 words

The fiber optic coupler as in claim 8 wherein said falloff in light intensity is no more than 3 dB.

Claim 11

Dependent Claim 79 words

The fiber optic coupler as in claim 2 wherein said second optic fibers comprise single mode fibers, said end sections of said second optical fibers having a taper angle of θ° in the range of 0.25 to 0.26° where θ=tan.sup.-1 {(D.sub.o -D.sub.f)/2L} where D o is the cladding diameter of said second optical fiber, D f is the smallest diameter of the etched second optical fiber, and L is the length of the taper of said second optical fiber.

Claim 12

Dependent Claim 78 words

The fiber optic coupler as in claim 2 wherein said second optic fibers comprise multimode fibers, said end sections of said second optical fibers having a taper angle of θ° in the range of 0.17 to 0.21° where θ=tan.sup.-1 {(D.sub.o -D.sub.f)/2L} where D o is the cladding diameter of said second optical fiber, D f is the smallest diameter of the etched second optical fiber, and L is the length of the taper of said second optical fiber.

Claim 13

Dependent Claim 26 words

The fiber optic coupler as in claim 2 wherein said microlens of said first optic fiber is displaced from said first side of said GRIN lens.

Claim 14

Dependent Claim 25 words

The fiber optic coupler as in claim 12 wherein said microlens is displaced in the range of 0.010 to 0.015 mm. from said first side.

Claim 15

Dependent Claim 29 words

The fiber optic coupler as in claim 12 wherein said first fiber comprises a single mode fiber and said microlens has a radius of curvature of approximately 10 microns.

Claim 16

Dependent Claim 28 words

The fiber optic coupler as in claim 12 wherein said first fiber comprises a multimode fiber and said microlens has a radius of curvature of approximately 35 microns.

Claim 17

Dependent Claim 10 words

The fiber optic coupler as in claim 1 wherein N>16.

Claim 18

Dependent Claim 19 words

The fiber optic coupler as in claim 16 wherein said first and second optical fibers comprise multimode optical fibers.

Claim 19

Dependent Claim 20 words

The fiber optic coupler as in claim 16 wherein said first and second optical fibers comprise single mode optical fibers.

Claim 20

Dependent Claim 17 words

The fiber optic coupler as in claim 1 wherein said GRIN lens comprises a quarter-pitch GRIN lens.

Claim 21

Dependent Claim 75 words

A GRIN lens-optic fiber combination comprising a GRIN lens having a first side and an optical axis therethrough; and an optic fiber having a tip and a microlens at said tip, said tip aligned along said GRIN lens optical axis and displaced a predetermined distance away from said first side; whereby a light signal from said fiber appears to be a point source at said first side on said optic axis of said GRIN lens.

Claim 22

Dependent Claim 75 words

A GRIN lens-optic fiber combination comprising a GRIN lens having a first side and an optical axis therethrough; and an optic fiber having a tip and a microlens at said tip, said tip aligned along said GRIN lens optical axis and displaced a predetermined distance away from said first side; whereby a light signal from said fiber appears to be a point source at said first side on said optic axis of said GRIN lens.

Claim 23

Dependent Claim 15 words

The combination as in claim 20 wherein said GRIN lens comprises a quarter-pitch GRIN lens.

Claim 24

Dependent Claim 19 words

The combination as in claim 21 wherein said predetermined distance is in the range of 0.010 to 0.015 mm.

Claim 25

Dependent Claim 15 words

The combination as in claim 22 wherein said first side is coated with anti-reflection material.

Claim 26

Dependent Claim 53 words

A bundle of optic fibers comprising each fiber having a cladding, core and an end section tapered so that at least said core at the end of said fiber is exposed; and a binding material bundling said end sections together, said material having an index of refraction less than that of said core.

Claim 27

Dependent Claim 53 words

A bundle of optic fibers comprising each fiber having a cladding, core and an end section tapered so that at least said core at the end of said fiber is exposed; and a binding material bundling said end sections together, said material having an index of refraction less than that of said core.

Claim 28

Dependent Claim 13 words

The fiber bundle as in claim 24 wherein said binding material comprises epoxy.

Claim 29

Dependent Claim 32 words

The fiber bundle as in claim 24 wherein the tips of said end sections are aligned so that the ends of said fibers are perpendicular to the axis of optic fiber bundle.

Claim 30

Dependent Claim 22 words

The fiber bundle as in claim 24 further comprising a ferrule around said end sections to further bundle said end sections together.

Claim 31

Independent Claim 110 words

A method of manufacturing a 1×N fiber optic coupler comprising forming a microlens at an end of a first optic fiber; fixing said microlens end of said first fiber along an optical axis of a GRIN lens a predetermined distance away from a first surface of said GRIN lens so that a light signal from said first optical fiber appears to emanate from a point source at said first surface of said GRIN lens; and fixing a bundle of tapered end sections of at least N second optical fibers along said optical axis of said GRIN lens and against a second surface of said GRIN lens opposite said first surface.

Claim 32

Independent Claim 110 words

A method of manufacturing a 1×N fiber optic coupler comprising forming a microlens at an end of a first optic fiber; fixing said microlens end of said first fiber along an optical axis of a GRIN lens a predetermined distance away from a first surface of said GRIN lens so that a light signal from said first optical fiber appears to emanate from a point source at said first surface of said GRIN lens; and fixing a bundle of tapered end sections of at least N second optical fibers along said optical axis of said GRIN lens and against a second surface of said GRIN lens opposite said first surface.

Claim 33

Dependent Claim 19 words

The method as in claim 28 wherein said predetermined distance is in the range from 0.010 to 0.015 mm.

Claim 34

Dependent Claim 34 words

The method as in claim 28 further comprising the step of tapering each end section of said second optical fibers such that at least the core is exposed at the end of each fiber.

Claim 35

Dependent Claim 34 words

The method as in claim 30 further comprising the step of bundling said second fiber end sections with a binding material having an index of refraction less than that of said second fiber core.

Claim 36

Dependent Claim 12 words

The method as in claim 31 wherein said binding material comprises epoxy.

Claim 37

Dependent Claim 35 words

The method as in claim 32 wherein said bundling step comprises inserting said end sections into a ferrule so that the said end sections extend through said ferrule to expose the ends of said fibers.

Claim 38

Dependent Claim 38 words

The method as in claim 31 further comprising the step of aligning the tips of said second optic fibers so that the ends of said second optic fibers are perpendicular to the axis of said optical fiber bundle.

Claim 39

Independent Claim 63 words

A method of manufacturing a bundle of optical fibers, each fiber having a cladding and a core, comprising tapering an end section of each optical fiber so that at least the core at the end of said fiber is exposed, and bundling said tapered end sections together with a binding material having an index of refraction less than that of said fiber core.

Claim 40

Independent Claim 63 words

A method of manufacturing a bundle of optical fibers, each fiber having a cladding and a core, comprising tapering an end section of each optical fiber so that at least the core at the end of said fiber is exposed, and bundling said tapered end sections together with a binding material having an index of refraction less than that of said fiber core.

Claim 41

Dependent Claim 12 words

The method as in claim 35 wherein said binding material comprises epoxy.

Claim 42

Dependent Claim 34 words

The method as in claim 36 further comprising the step of aligning the tips of said fibers so that the ends of said fibers are perpendicular to the axis of said optical fiber bundle.

Claim 43

Dependent Claim 35 words

The method as in claim 35 wherein said bundling step comprises inserting said end sections into a ferrule so that the said end sections extend through said ferrule to expose the ends of said fibers.

Annuity Stage	Window Opens	Payment Deadline	Surcharge Period Until	Estimated Fee	Status
3.5 Years (Year 4)	1994-05-20	1994-11-19	1995-05-21	$2000.00	Window Closed / Lapsed
7.5 Years (Year 8)	1998-05-20	1998-11-19	1999-05-21	$3760.00	Window Closed / Lapsed
11.5 Years (Year 12)	2002-05-20	2002-11-19	2003-05-21	$7700.00	Window Closed / Lapsed

Fiber optic coupler and method of making same

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