Local area network optical fiber data communication
First Claim
1. An optical data communication system comprising a plurality of stations linked together by a multimode optical waveguide to form an optical signal, each of said stations comprising:
- an array of lasers,a switching matrix for controlling the propagation of radiation from said lasers into said optical waveguide,a multiplexer/coupler for coupling radiation from said lasers to said waveguide, radiation from different lasers being coupled to different angular modes of propagation in said waveguide,a coupler/demultiplexer for demultiplexing radiation received at said station from said waveguide,an optical pulse regenerator coupled to said coupler/demultiplexer, said pulse regenerator having a threshold level above which the optical signal is optically amplified and reshaped and below which the signal is suppressed, andan optical processor to which is applied the optical signal from the pulse regenerator, said optical processor including optical logic circuits for detecting the address of data packets contained in signals transmitted along said optical waveguide and for routing said signals either to a host computer at said station or to said switching matrix.
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Abstract
A method and apparatus are disclosed for high speed multiaccess data communication using guided wave components and angular division multiplexing for parallel optical signal transmission over a multimode optical fiber. A receiver at each station in the network comprises an optical coupler/demultiplexer, a pulse regenerator, an optical processor and detectors. The transmitter at each station comprises an array of lasers, a switching matrix for controlling emissions into the optical fiber and a multiplexer/coupler for coupling the laser emissions to the multimode optical fiber. The optical processor is directly coupled to the switching matrix. Preferably, the multiplexer/coupler comprises a graded-index planar lens, one major surface of which abuts the optical fiber and the other major surface of which is contacted by a plurality of single mode waveguides from the different lasers of the transmitter. As a result, the single mode signals introduced into the lens at different radial distances are coupled to different modal groups propagating in the optical fiber. The coupler/demultiplexer preferably comprises a graded-index lens and an array of concentric half-ring lasers. Annular cones of radiation propagating in the optical fiber are focused to an array of concentric rings near the half-ring lasers where they are converted into linear beams propagating in single mode guided wave structures.
288 Citations
18 Claims
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1. An optical data communication system comprising a plurality of stations linked together by a multimode optical waveguide to form an optical signal, each of said stations comprising:
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an array of lasers, a switching matrix for controlling the propagation of radiation from said lasers into said optical waveguide, a multiplexer/coupler for coupling radiation from said lasers to said waveguide, radiation from different lasers being coupled to different angular modes of propagation in said waveguide, a coupler/demultiplexer for demultiplexing radiation received at said station from said waveguide, an optical pulse regenerator coupled to said coupler/demultiplexer, said pulse regenerator having a threshold level above which the optical signal is optically amplified and reshaped and below which the signal is suppressed, and an optical processor to which is applied the optical signal from the pulse regenerator, said optical processor including optical logic circuits for detecting the address of data packets contained in signals transmitted along said optical waveguide and for routing said signals either to a host computer at said station or to said switching matrix. - View Dependent Claims (2, 3)
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4. An optical multiplexer/coupler for coupling single mode optical signals to a multimode optical waveguide said multiplexer/coupler comprising:
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a planar lens having a first major surface which abuts the end of said multimode optical waveguide, said planar lens having an index of refraction which decreases with the square of the radial distance from the optical axis of said waveguide, and a plurality of optical waveguides contacting a second major surface of said planar lens at different radial distances from said optical axis. - View Dependent Claims (5, 6, 7)
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8. An optical coupler/demultiplexer for demultiplexing multimode optical signals, said coupler demultiplexer comprising:
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a lens having a first major surface which abuts the end of a multimode optical waveguide, said lens having an index of refraction which decreases with the square of the radial distance from the optical axis of said fiber, said lens focusing discrete annular cones of radiation propagating within said fiber to annular rings near a second major surface of said lens, a plurality of half-ring lasers facing said second major surface of said lens and being aligned with a portion of the annular rings formed by said lens, and a plurality of optical waveguides disposed to transmit radiation from individual half-ring lasers. - View Dependent Claims (9, 10, 11)
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12. An optical data communication system comprising a plurality of stations linked together by a step-index multimode optical waveguide, each of said stations comprising:
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an array of sources of optical electromagnetic radiation, means for controlling the propagation of radiation from said sources into said optical waveguide, means for coupling radiation from said sources to said waveguide, radiation from different sources being coupled to different angular modes of propagation in said step-index waveguide, means for demultiplexing radiation received at said station from said waveguide, and means for detecting said demultiplexed radiation.
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13. In an optical data communication system comprising a plurality of stations linked together by a step-index multimode optical waveguide, a method of operating a station of said system comprising the steps of:
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modulating a plurality of beams of optical electromagnetic radiation with information to be transmitted, coupling said modulated beams of radiation to said waveguide, radiation from different beams being coupled to different angular modes of propagation in said step-index waveguide, demultiplexing radiation received at said station from said waveguide, and detecting said demultiplexed radiation.
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14. An optical data communication system comprising a plurality of stations linked together by a multimode optical waveguide, each of said stations comprising:
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an array of sources of electromagnetic radiation, means for controlling the propagation of radiation from said sources into said optical waveguide to form an optical signal, a multiplexer/coupler for coupling radiation from said sources to said waveguide, radiation from different sources being coupled to different angular modes of propagation in said waveguide, a coupler/demultiplexer for demultiplexing radiation received at said station from said waveguide, an optical pulse regenerator coupled to said coupler/demultiplexer, said pulse regenerator having a threshold level above which the optical signal is optically amplified and reshaped and below which the signal is suppressed, and an optical processor to which is applied the optical signal from the pulse regenerator, said optical processor including optical logic circuits for detecting the address of data packets contained in signals transmitted along said optical waveguide and for routing said signals either to data processing equipment at said station or to said means for controlling the propagation of radiation from said sources. - View Dependent Claims (15, 16)
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17. An optical multiplexer/coupler for coupling single mode optical signals to a multimode optical waveguide said multiplexer/coupler comprising:
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a lens having a first major surface which abuts the end of said multimode optical waveguide, said lens having an index of refraction which decreases with the square of the radial distance from the optical axis of said waveguide, and a plurality of optical waveguides contacting a second major surface of said lens at different radial distances from said optical axis. - View Dependent Claims (18)
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Specification