Coupler for optical waveguide light source

Claim 2

An optical communication system comprising light transmitting means including at least one optical waveguide for propagating optical wave energy, a light coupler having a tapered core of transparent material and a layer of transparent cladding material disposed upon the surface of said core, the refractive index n1 of said core material being greater than the refractive index n2 of said transparent cladding material, said core having a small diameter endface and a large diameter endface, both said endfaces being perpendicular to the axis of said core, the refractive index of said tapered core varying throughout the length thereof, the refractive index at the large diameter end of said core being less than that at the small diameter end thereof, means for supporting the large diameter endface of said core adjacent to an end of said light transmitting means so that said core is aligned with the light transmitting area of said light transmitting means, and light source means disposed adjacent to the small diameter endface of said core for directing light onto the small diameter endface of said core.

Claim 3

An optical communication system in accordance with claim 1 wherein the taper half-angle Beta of said core is given by the following equation NAin Square Root n12 - n22 cos Beta + n2 sin Beta where NAin is a predetermined input numerical aperture, and the axial length L of said coupler is given by the following equation L (A - R) cot Beta where A is the radius of the light emitting area of said light source means and R is effective light transmitting area of said light transmitting means.

Claim 4

An optical communication system in accordance with claim 1 wherein said light transmitting means comprises a bundle of optical waveguides disposed in side-by-side relation.

Claim 5

An optical communication system in accordance with claim 1 wherein said light transmitting means comprises a single optical waveguide, the core of which is substantially aligned with the large diameter end of said coupler core.

Claim 6

An optical communication system in accordance with claim 1 wherein the refractive index of said core varies gradually.

Claim 7

An optical communication system in accordance with claim 1 wherein said core consists of a plurality of regions each having a refractive index different from the adjacent region.

Claim 8

An optical communication system in accordance with claim 1 wherein said light source means comprises a light emitting diode the light emitting area of which is disposed adjacent to the small diameter end of said core, said small diameter end being at least as large as said light emitting area of said diode.

Claim 9

In an optical communication system of the type comprising a fiber bundle having a plurality of optical waveguides disposed in side-by-side relation, a light emitting diode having a first surface from which light is emitted, a light coupler having an input end for receiving light from said diode and an output end for emitting light into said fiber bundle, said coupler being characterized in that it comprises a tapered core of transparent material, said tapered core having a polished small diameter endface disposed adjacent to said first surface of said diode, and a large diameter endface at the output end of said coupler, the refractive index of said tapered core varying throughout the length thereof, the refractive index at the large diameter end of said core being less than that at the small diameter end thereof, a layer of transparent cladding material disposed upon the surface of said core, the refractive index of said tapered core material being greater than that of said coupler cladding material, the minimum thickness of said coupler Cladding layer being at least ten times the wavelength of light which said source is adapted to provide, and means for supporting said large diameter endface adjacent to an end of said fiber bundle so that said tapered core is aligned with the light transmitting area of said fiber bundle and light radiating from said coupler initiates the propagation of light waves in the optical waveguides of said bundle.

Claim 10

In an optical communication system of the type comprising a fiber bundle having a plurality of optical waveguides disposed in side-by-side relation, a light emitting diode having a first surface from which light is emitted, a light coupler having an input end for receiving light from said diode and an output end for emitting light into said fiber bundle, said coupler being characterized in that it comprises a tapered core of transparent material, said tapered core having a polished small diameter endface disposed adjacent to said first surface of said diode, and a large diameter endface at the output end of said coupler, the refractive index of said tapered core varying throughout the length thereof, the refractive index at the large diameter end of said core being less than that at the small diameter end thereof, a layer of transparent cladding material disposed upon the surface of said core, the refractive index of said tapered core material being greater than that of said coupler cladding material, the minimum thickness of said coupler Cladding layer being at least ten times the wavelength of light which said source is adapted to provide, and means for supporting said large diameter endface adjacent to an end of said fiber bundle so that said tapered core is aligned with the light transmitting area of said fiber bundle and light radiating from said coupler initiates the propagation of light waves in the optical waveguides of said bundle.

Claim 11

An optical communication system in accordance with claim 8 wherein the area of said small diameter endface of said tapered core is substantially equal to that of the light transmitting portion of the first surface of said diode.

Claim 12

An optical communication system in accordance with claim 8 wherein the refractive index of said core varies gradually.

Claim 13

An optical communication system in accordance with claim 8 wherein said core consists of a plurality of regions, each having a refractive index different from the adjacent region.

Claim 14

An optical communication system comprising a light emitting diode for providing optical signals, a fiber bundle having a plurality of optical waveguides disposed in side-by-side relation, all of said waveguides being adapted to transmit said optical signals, a light coupler having a tapered core of transparent material and a layer of transparent cladding material disposed upon the surface of said core, the refractive index of said core material being greater than that of said cladding material, said core having large and small diameter endfaces that are perpendicular to the axis thereof, the small diameter endface of said core being disposed adjacent to the light emitting area of said diode, said small diameter endface being at least as large as said light emitting area of said diode, and means for supporting said large diameter endface adjacent to an end of said fiber bundle so that said large diameter end face is aligned with the light transmitting area of said fiber bundle and optical signals emitted by said diode are propagated in all of the waveguides of said bundle.

Claim 15

An optical communication system comprising a light emitting diode for providing optical signals, a fiber bundle having a plurality of optical waveguides disposed in side-by-side relation, all of said waveguides being adapted to transmit said optical signals, a light coupler having a tapered core of transparent material and a layer of transparent cladding material disposed upon the surface of said core, the refractive index of said core material being greater than that of said cladding material, said core having large and small diameter endfaces that are perpendicular to the axis thereof, the small diameter endface of said core being disposed adjacent to the light emitting area of said diode, said small diameter endface being at least as large as said light emitting area of said diode, and means for supporting said large diameter endface adjacent to an end of said fiber bundle so that said large diameter end face is aligned with the light transmitting area of said fiber bundle and optical signals emitted by said diode are propagated in all of the waveguides of said bundle.

Claim 16

A transmission system for the purpose of guiding optical wave energy comprising in longitudinal axial alignment, a light source, a light coupling section of fiber having a tapered core of transparent material and a layer of transparent cladding material disposed upon the surface of said tapered core, the refractive index of said core material being greater than that of the cladding, and an optical waveguide section of fiber, wherein the refractive index of the core of said tapered coupling section of fiber decreases longitudinally from a predetermined value at the small end thereof adjacent said light source to a lower value at the large end adjacent said waveguide section.

Claim 17

A transmission system for the purpose of guiding optical wave energy comprising in longitudinal axial alignment, a light source, a light coupling section of fiber having a tapered core of transparent material and a layer of transparent cladding material disposed upon the surface of said tapered core, the refractive index of said core material being greater than that of the cladding, and an optical waveguide section of fiber, wherein the refractive index of the core of said tapered coupling section of fiber decreases longitudinally from a predetermined value at the small end thereof adjacent said light source to a lower value at the large end adjacent said waveguide section.