MULTIPLEXED OPTICAL COMMUNICATIONS SYSTEM
First Claim
1. A multiplexed optical communication system comprising a plurality of coherent light beam sources for producing light beams each in the form of a light pUlse train having a substantially equal predetermined repetition rate, means disposed in the light paths of said light beam for respectively ON-OFF modulating said light pulse sources in response to pulsed information signals to be transmitted, a light transmission path for transmitting the modulated light beams, a plurality of thin fibrous converging light guide elements for optically coupling said modulating means to said light transmission path, one end of each of said light guide elements being disposed facing said modulating means in one-to-one correspondence, the other ends of each of said light guide elements being arranged in a bundle with their optical axes being substantially aligned with that of the input end portion of said transmission path, each of said light guide elements having a refractive index distribution which is greatest along its longitudinal axis and which decreases monotonically toward its surface substantially in proportion to the square of the radial distance from said axis and having a cross section much smaller than the aperture of said input end portion of said transmission path, and means for receiving the modulated light beams transmitted through said transmission path and for detecting said pulsed information signals from the received light beams separately one from another, said modulating means including means for providing a predetermined phase relationship between the light pulse trains of said light beams, the lengths of said light guide elements being different from one another to provide a different retardation to the respective light beams, thereby to produce time-division-multiplexed light pulse trains at the bundled end of said light guide elements, whereby said modulated light pulse trains travel through said transmission path in a time-division multiplexed fashion.
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Abstract
A multiplexed optical communications system comprises a plurality of fibrous light guide elements which receive respective ones of a plurality of modulated light beam sources having predetermined phase differences therebetween. The output ends of the elements are formed into a bundle which communicates with one end of a light transmission path. Means positioned at the other end of the transmission path are provided for separating the modulated signals in accord with their respective phase separations.
19 Citations
3 Claims
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1. A multiplexed optical communication system comprising a plurality of coherent light beam sources for producing light beams each in the form of a light pUlse train having a substantially equal predetermined repetition rate, means disposed in the light paths of said light beam for respectively ON-OFF modulating said light pulse sources in response to pulsed information signals to be transmitted, a light transmission path for transmitting the modulated light beams, a plurality of thin fibrous converging light guide elements for optically coupling said modulating means to said light transmission path, one end of each of said light guide elements being disposed facing said modulating means in one-to-one correspondence, the other ends of each of said light guide elements being arranged in a bundle with their optical axes being substantially aligned with that of the input end portion of said transmission path, each of said light guide elements having a refractive index distribution which is greatest along its longitudinal axis and which decreases monotonically toward its surface substantially in proportion to the square of the radial distance from said axis and having a cross section much smaller than the aperture of said input end portion of said transmission path, and means for receiving the modulated light beams transmitted through said transmission path and for detecting said pulsed information signals from the received light beams separately one from another, said modulating means including means for providing a predetermined phase relationship between the light pulse trains of said light beams, the lengths of said light guide elements being different from one another to provide a different retardation to the respective light beams, thereby to produce time-division-multiplexed light pulse trains at the bundled end of said light guide elements, whereby said modulated light pulse trains travel through said transmission path in a time-division multiplexed fashion.
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2. The multiplexed optical communication system as claimed in claim 1, wherein said light transmission path comprises a lens system and the atmosphere.
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3. The multiplexed optical communication system as claimed in claim 2, wherein said light transmission path comprises a long-distance light guide element having a cross section greater than that of said fibrous light guide elements and having a refractive index distribution similar to the latter.
Specification
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Current AssigneeMotoaki Furukawa, Teiji Uchida
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Original AssigneeMotoaki Furukawa, Teiji Uchida
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InventorsUchida, Teiji, Furukawa, Motoaki
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Primary Examiner(s)Safourek, Benedict V.
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Application NumberUS04/876,357Time in Patent Office782 DaysField of Search250/199,227 350/96B,96WG,156,169 178/6,DIG.2US Class Current398/101CPC Class CodesH04B 10/25891 Transmission components H04...
