Tapered coupler for optical communication system

Claim 2

In an optical communication system having a first plurality of optical signal transmission lines which are to communicate with a first optical signal transmission line, wherein each of said transmission lines comprises at least one optical waveguide having a core of transparent material having a refractive index n1 surroundeD by a layer of transparent cladding material having a refractive index n2 that is lower than n1, a coupler for coupling different optical signals between each of said first plurality of transmission lines and said first transmission line, said coupler comprising an elongated rod in the shape of a truncated cone, said rod having large and small substantially parallel, planar, circularly shaped endfaces that are substantially perpendicular to the axis thereof, said rod consisting of transparent material having a refractive index n3 that is substantially equal to n1, a layer of transparent cladding material disposed upon the surface of said rod and forming with the surface thereof a light reflecting interface, the refractive index n4 of said cladding material being lower than n3, means at said small endface for preventing light from said rod from reflecting from said small endface back into said rod, first support means for disposing the end portions of said first plurality of transmission lines in a bundled, parallel arrangement, the optical wave-guides of which said transmission lines are comprised terminating in faces that are disposed adjacent to said large endface, said faces being disposed in a planar array that is substantially parallel to said large endface, said waveguide faces being circumscribed by a circle of radius R, the diameter of said first transmission line being r, the minimum length Lm of said rod being defined by the equation

Claim 3

An optical communication system in accordance with claim 1 wherein the maximum taper angle of said rod is theta c/2.

Claim 4

An optical communication system in accordance with claim 2 wherein the ends of each of said first plurality of said transmission lines and the end of said first transmission line which are remote from said coupler terminate at optical signal coupling means.

Claim 5

An optical communication system in accordance with claim 3 further comprising a plurality of stations equal in number to one plus the number of said first plurality of transmission lines, a second plurality of optical signal transmission lines equal in number to the number of said stations, each of said stations being connected by one of said second plurality of transmission lines to a respective one of said coupling means each of said stations including means for generating optical signals and means for receiving optical signals.

Claim 6

In an optical communication system having a coupler for connecting optical signals from a first station to a plurality of stations and connecting optical signals from said plurality of stations to said first station but preventing the interconnection of optical signals from one of said plurality of stations to another of said plurality of stations, wherein said first station and said plurality of stations each includes means for generating an optical signal and means for receiving an optical signal, a first optical signal transmission line for connecting said first station to said coupler and a plurality of optical signal transmission lines, one of which connects each of said plurality of stations to said coupler, wherein each of said transmission lines comprises at least one optical waveguide having a core of transparent material having a refractive index n1 surrounded by a layer of transparent cladding material having a refractive index n2 that is lower than n1, said coupler being characterized in that it comprises an elongated, tapered rod of transparent material having lArge and small substantially parallel planar endfaces that are substantially perpendicular to the axis thereof, means at said small endface for preventing light from said rod from reflecting from said small endface back into said rod, means surrounding said rod for forming with the surface thereof a light reflecting interface, first support means for disposing the end portions of said plurality of transmission lines in a bundled, parallel arrangement, the optical waveguides of which said transmission lines are comprised terminating in faces that are disposed adjacent to said large endface, said faces being disposed in a planar array that is substantially parallel to said large endface, and second support means for disposing the end portion of said first transmission line adjacent to said small endface, the axis of said first transmission line being substantially parallel to that of said rod.

Claim 7

In an optical communication system having a coupler for connecting optical signals from a first station to a plurality of stations and connecting optical signals from said plurality of stations to said first station but preventing the interconnection of optical signals from one of said plurality of stations to another of said plurality of stations, wherein said first station and said plurality of stations each includes means for generating an optical signal and means for receiving an optical signal, a first optical signal transmission line for connecting said first station to said coupler and a plurality of optical signal transmission lines, one of which connects each of said plurality of stations to said coupler, wherein each of said transmission lines comprises at least one optical waveguide having a core of transparent material having a refractive index n1 surrounded by a layer of transparent cladding material having a refractive index n2 that is lower than n1, said coupler being characterized in that it comprises an elongated, tapered rod of transparent material having lArge and small substantially parallel planar endfaces that are substantially perpendicular to the axis thereof, means at said small endface for preventing light from said rod from reflecting from said small endface back into said rod, means surrounding said rod for forming with the surface thereof a light reflecting interface, first support means for disposing the end portions of said plurality of transmission lines in a bundled, parallel arrangement, the optical waveguides of which said transmission lines are comprised terminating in faces that are disposed adjacent to said large endface, said faces being disposed in a planar array that is substantially parallel to said large endface, and second support means for disposing the end portion of said first transmission line adjacent to said small endface, the axis of said first transmission line being substantially parallel to that of said rod.

Claim 8

An optical communication system in accordance with claim 5 wherein said rod is in the shape of a truncated cone and said large and small endfaces are circular, and wherein said plurality of transmission lines are grouped into a bundle, the cross-section of which is circumscribed by a circle of radius R, the diameter of said first transmission line being r, the minimum length Lm of said rod being defined by the equation

Claim 9

An optical communication system in accordance with claim 6 wherein the maximum taper angle of said rod is theta c/2.