Passive optical coupler

Claim 2

A passive optical coupler for use in an optical communication system including first and second optical signal transmission lines, said coupler comprising, first and second light mixers, each having an input portion for receiving light and an output portion across which light received by the input portion is relatively evenly distributed, the input portion of said first mixer being adapted to be connected to an end of said first transmission line, and the output portion of said second mixer being adapted to be connected to an end of said second transmission line, first coupling means for coupling most of the light at the output portion of said first mixer to the input portion of said second mixer, the remaining light available at the output portion of said first mixer constituting an output optical signal, output means for receiving said output optical signal, second coupling means disposed adjacent to the output portion of said first mixer for coupling said output optical signal to said output means, input means for providing an input optical signal, and third coupling means for coupling said input optical signal from said input means to the input portion of said second mixer.

Claim 3

A coupler in accordance with claim 1 wherein said first and second mixers comprise first and second elongated transparent rods, the input and output portion of each rod consisting of planar endfaces that are perpendicular to the axis thereof, and wherein said first coupling means comprises a first bundle of optical waveguide fibers connected between the output endface of said first rod and the input endface of said second rod.

Claim 4

A coupler in accordance with claim 2 wherein said second and third coupling means comprise second and third bundles of optical waveguide fibers, respectively, a first end of said second bundle being disposed adjacent to the output endface of said first elongated rod, a second end of said second bundle being coupled to said output means, a first end of said third bundle being disposed adjacent to said input means and a second end of said third bundle being disposed adjacent to said input endface of said second elongated rod.

Claim 5

A coupler in accordance with claim 3 wherein said output means is a light detector disposed adjacent to said second end of said second bundle, and said input means is a light source disposed adjacent to said first end of said third bundle.

Claim 6

A coupler in accordance with claim 3 further comprising first and second tapered rods having endfaces substantially perpendicular to the axes thereof, said small endface of said first tapered rod being disposed adjacent to said second end of said second bundle, said small endface of said second tapered rod being disposed adjacent to said first end of said third bundle, a third optical signal transmission line coupled to the large endface of said first tapered rod and a fourth optical signal transmission line coupled to the large endface of said second tapered rod.

Claim 7

A coupler in accordance with claim 1 wherein said first and second mixers and said first, second and third coupling means comprise an elongated transparent member having first and second opposed end portions respectively terminating in planar input and output endfaces which are perpendicular to the axis of said elongated member, the cross-sectional area of said first and second end portions approximating the cross-sectional area of said first and second sections of transmission line, said input endface being disposed adjacent to an end of said first section of transmission line and said output endface being disposed adjacent to an end of said second section of transmission line, the cross-sectional area of the central portion of said elongated member being less than that of said first and second end portions, first and second elongated furcated portions extending from that part of said first and second end portions, respectively, opposite said endfaces, said furcated portions curving away from the central portion of said elongated member, the end of said first furcated portion remote from said first end portion being coupled to said output means, and the end of said second furcated portion remote from said second end portion being coupled to said input means.

Claim 8

A passive optical coupler for use in an optical communication system including first and second optical signal transmission lines, said coupler comprising, first and second light mixers, each having an input portion for receiving light and an output portion across which light received by the input portion is relatively evenly distributed, the input portion of said first mixer being adapted to be connected to an end of said first transmission line, and the output portion of said second mixer being adapted to be connected to an end of said second transmission line, third optical signal transmission line coupling means for coupling the light at the output portion of said first mixer to the input portion of said second mixer, the remaining light available at the output portion of said first mixer constituting an output optical signal, fourth optical signal transmission line coupling means disposed adjacent to the output portion of said first mixer for coupling said output optical signal from said mixer, and fifth optical signal transmission line coupling means for coupling an input optical signal to the input portion of said second mixer.

Claim 9

A passive optical coupler for use in an optical communication system including first and second optical signal transmission lines, said coupler comprising, first and second light mixers, each having an input portion for receiving light and an output portion across which light received by the input portion is relatively evenly distributed, the input portion of said first mixer being adapted to be connected to an end of said first transmission line, and the output portion of said second mixer being adapted to be connected to an end of said second transmission line, third optical signal transmission line coupling means for coupling the light at the output portion of said first mixer to the input portion of said second mixer, the remaining light available at the output portion of said first mixer constituting an output optical signal, fourth optical signal transmission line coupling means disposed adjacent to the output portion of said first mixer for coupling said output optical signal from said mixer, and fifth optical signal transmission line coupling means for coupling an input optical signal to the input portion of said second mixer.