System for transmitting and receiving plural messages via a single fiber-optical path

Claim 1

A system for simultaneously conveying a plurality of messages between a transmitting station and a receiving station interconnected by a light-conductive path, comprising: a number m>2 of sources of monochromatic light beams of different wavelengths modulated by respective messages at said transmitting station; a like number m>2 of demodulators for said light beams at said receiving station; first light-guiding means at said transmitting station inserted between said sources and said path for combining said monochromatic light beams into a single composite beam traveling over said path; and second light-guiding means at said receiving station inserted between said path and said demodulators for splitting said composite beam into its constituent monochromatic beams respectively fed to said demodulators; at least one of said light-guiding means including a common transparent body with flat faces adjoining each other at obtuse angles and (m-1) other transparent bodies each contacting one of said faces, said contacting bodies having refractive indices varying as a function of wavelength along respective curves of different slope, the refractive-index curve of said common body intersecting the refractive-index curve of each one of said adjoining bodies at a point which substantially corresponds to the wavelength of one of said monochromatic beams whereby the latter passes substantially undeflected through the interface between said common body and a respective one of said adjoining bodies, the refractive indices of said contacting bodies for the wavelength of any other monochromatic beam traversing said common body being sufficiently different from that of said common body to establish a critical angle of incidence whose complement at least equals the glancing angle by which such other beam strikes said interface whereby each such other beam is reflected at said interface and passes entirely within said common body from one interface to the next.

Claim 2

A system for simultaneously conveying a plurality of messages between a transmitting station and a receiving station interconnected by a light-conductive path, comprising: a number m>2 of sources of monochromatic light beams of different wavelengths modulated by respective messages at said transmitting station; a like number m>2 of demodulators for said light beams at said receiving station; first light-guiding means at said transmitting station inserted between said sources and said path for combining said monochromatic light beams into a single composite beam traveling over said path; and second light-guiding means at said receiving station inserted between said path and said demodulators for splitting said composite beam into its constituent monochromatic beams respectively fed to said demodulators; at least one of said light-guiding means including a common transparent body with flat faces adjoining each other at obtuse angles and (m-1) other transparent bodies each contacting one of said faces, said contacting bodies having refractive indices varying as a function of wavelength along respective curves of different slope, the refractive-index curve of said common body intersecting the refractive-index curve of each one of said adjoining bodies at a point which substantially corresponds to the wavelength of one of said monochromatic beams whereby the latter passes substantially undeflected through the interface between said common body and a respective one of said adjoining bodies, the refractive indices of said contacting bodies for the wavelength of any other monochromatic beam traversing said common body being sufficiently different from that of said common body to establish a critical angle of incidence whose complement at least equals the glancing angle by which such other beam strikes said interface whereby each such other beam is reflected at said interface and passes entirely within said common body from one interface to the next.

Claim 4

A system for simultaneously conveying a plurality of messages between a transmitting station and a receiving station interconnected by a light-conductive path, comprising: a number m>2 of sources of monochromatic light beams of different wavelengths modulated by respective messages at said transmitting station; a like number m>2 of demodulators for said light beams at said receiving station; first light-guiding means at said transmitting station inserted between said sources and said path for combining said monochromatic light beams into a single composite beam traveling over said path; second light-guiding means at said receiving station inserted between said path and said demodulators for splitting said composite beam into its constituent monochromatic beams respectively fed to said demodulators, at least one of said light-guiding means including m-1 transparent bodies in cascade with at least one intervening air gap bounded by faces perpendicular to the beam direction, each of said bodies consisting of two portions adjoining each other along an interface, said portions having refractive indices varying as a function of wavelength along curves of different slope intersecting at a common point which substantially corresponds to the wavelength of one of said monochromatic beams whereby the latter passes substantially undeflected through said interface, the refractive indices of said portions for the wavelength of any other monochromatic beam traversing said body being sufficiently different from each other to establish a critical angle of incidence whose complement at least equals the glancing angle by which such other beam strikes said interface whereby each such other beam is reflected at said interface, the reflected beams of any preceding body in the cascade being trained upon the interface of an immediately succeeding body; and focusing means inserted in said air gap for concentrating the light rays of said composite beam.

Claim 5

A system for simultaneously conveying a plurality of messages between a transmitting station and a receiving station interconnected by a light-conductive path, comprising: a number m>2 of sources of monochromatic light beams of different wavelengths modulated by respective messages at said transmitting station; a like number m>2 of demodulators for said light beams at said receiving station; first light-guiding means at said transmitting station inserted between said sources and said path for combining said monochromatic light beams into a single composite beam traveling over said path; second light-guiding means at said receiving station inserted between said path and said demodulators for splitting said composite beam into its constituent monochromatic beams respectively fed to said demodulators, at least one of said light-guiding means including m-1 transparent bodies in cascade with at least one intervening air gap bounded by faces perpendicular to the beam direction, each of said bodies consisting of two portions adjoining each other along an interface, said portions having refractive indices varying as a function of wavelength along curves of different slope intersecting at a common point which substantially corresponds to the wavelength of one of said monochromatic beams whereby the latter passes substantially undeflected through said interface, the refractive indices of said portions for the wavelength of any other monochromatic beam traversing said body being sufficiently different from each other to establish a critical angle of incidence whose complement at least equals the glancing angle by which such other beam strikes said interface whereby each such other beam is reflected at said interface, the reflected beams of any preceding body in the cascade being trained upon the interface of an immediately succeeding body; and focusing means inserted in said air gap for concentrating the light rays of said composite beam.