Charles Kao Ph.D.

The Nobel Prize in Physics 2009
Co-nobelist: Willard S. Boyle, George E. Smith

Prize motivation: "for groundbreaking achievements concerning the transmission of light in fibers for optical communication."

Patents

Publication:	1/15
Publication No:	US4775972
Title:	Optical fiber communication for local area networks with frequency-division-multiplexing
Publication Type:	Grant
Publication Date:	October 4, 1988
Filing Date:	May 10, 1985
Inventors:	Charles C. Ih, Charles K. Kao
Original Assignee:	ITT CORPORATION, 320 PARK AVENUE, NEW YORK, N.Y.
Abstract:	A method and associated system for providing multi-channel transmission of digital and broadband video information in optical fiber communication for local area networks through frequency-division-multiplexing, comprising the steps of generating a plurality of closely spaced optical carrier wave pairs with the optical carrier waves within each optical carrier wave pair having a predetermined separation frequency between one another, assigning each of the plurality of optical carrier wave pairs to a predetermined frequency slot and optically combining the plurality of optical carrier wave pairs to provide a multiplexed optical output wave. Advantageously, in addition to direct detection the plurality of optical carrier wave pairs may be detected by opto-electronic heterodyne detection and/or incoherent optical-heterodyne detection to electronically recover the optical carrier wave pairs..
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Publication:	2/15
Publication No:	US 4726011
Title:	Coherent optical fiber communication with frequency-division-multiplexing
Publication Type:	Grant
Publication Date:	Feb 16, 1988
Filing Date:	Apr 8, 1985
Inventors:	Charles C. Ih, Charles K. Kao
Original Assignee:	Itt Defense Communications, A Division Of Itt Corporation
Abstract:	The method and associated system for providing increased information carrying capacity in optical fiber communication through frequency-division-multiplexing, comprising the steps of generating a reference optical beam, generating a plurality of closely spaced optical carriers having frequencies which are coherently related to the reference frequency of the reference optical beam and which are capable of drifting with the reference frequency while maintaining coherence therewith, and combining the plurality of closely spaced optical carriers to provide a multiplexed optical output beam. Advantageously, a frequency tracking optical beam tracks the reference optical beam and the plurality of closely spaced optical carriers of the multiplexed optical output beam are optically heterodyne detected by the tracking optical beam to convert the plurality of closely spaced optical carriers into a microwave spectrum, so that the individual carrier frequencies present in the microwave spectrum which correspond to the frequencies of the plurality of closely spaced optical carriers may be electronically heterodyne detected and separated from the microwave spectrum.
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Publication:	3/15
Publication No:	US4265515
Title:	Optical fiber waveguide with effective refractive index profile
Publication Type:	Grant
Publication Date:	May 5, 1981
Filing Date:	Dec 11, 1978
Inventors:	Charles K. Kao
Original Assignee:	Itt Defense Communications, A Division Of Itt Corporation
Abstract:	This invention relates to cathode ray devices and more specifically to methods of and apparatus for generating, focussing, accelerating and modulating the intensity of electron beams in cathode ray devices. An object of this invention is to provide improved cathode ray generating and controlling.
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Publication:	4/15
Publication No:	US 4243298
Title:	High-strength optical preforms and fibers with thin, high-compression outer layers
Publication Type:	Grant
Publication Date:	Jan 6, 1981
Filing Date:	Oct 6, 1978
Inventors:	Charles K. Kao, Mokhtar S. Maklad
Original Assignee:	International Telephone And Telegraph Corporation
Abstract:	High-strength optical preforms and optical fibers, particularly useful in light-wave communication systems, are fabricated by techniques producing high surface compressive forces in thin outer layers. These result in substantially increased fiber tensile strength, durability, and fiber life. High surface stresses are achieved in three-layer and four-layer preforms and fibers by employing particular combinations of core, cladding, and layer compositions, dopants, coefficients of thermal expansion, and glass transition temperatures. Various suitable manufacturing methods are disclosed using chemical vapor deposition techniques. For example, preforms may be fabricated by external deposition of layers on a drawn core-glass rod, or by internal CVD methods in which layers are sequentially deposited within hollow tubular silica substrates that are then collapsed into solid preforms by known techniques. In the internal deposition methods, preform finishing techniques are also disclosed for removing excess substrate material so as to leave a high-strength compressive layer of substantially pure silica.
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Publication:	5/15
Publication No:	US 4217029
Title:	Interlocking precision optical fiber connector or support
Publication Type:	Grant
Publication Date:	Aug 12, 1980
Filing Date:	Mar 31, 1978
Inventors:	Charles K. Kao
Original Assignee:	International Telephone And Telegraph Corporation
Abstract:	A first optical fiber end is precisely aligned in the interstice between a plurality of relatively equal diameter cylindrical rods. The rods are of disparate lengths and the fiber as located in the interstice has its tip accurately aligned with respect to a reference surface of one of the rods. The alignment of the fiber in this manner permits a similar rod arrangement to interlock with the above described structure to enable a similarly supported fiber to be accurately positioned with respect to the first fiber due to the interlocking of the respective rod assemblies.
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Publication:	6/15
Publication No:	US 4183621
Title:	Optical fibers having improved fatique resistance Water resistant high strength fibers
Publication Type:	Grant
Publication Date:	Jan 15, 1980
Filing Date:	Dec 29, 1977
Inventors:	Charles K. Kao, Mokhtar S. Maklad
Original Assignee:	International Telephone And Telegraph Corporation
Abstract:	Optical communication fibers having improved fatigue resistance are provided by encapsulating the fibers in a water impervious material. The water impervious material prevents the interaction of water with glass along the fiber outer surface and prolongs the operational life-time of the fibers.
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Publication:7/15 Publication No:US 4134641 Title:Self centering connector design Publication Type:Grant Publication Date:Jan 16, 1979 Filing Date:May 17, 1977 Inventors:Charles K. Kao, James E. Goell Original Assignee:International Telephone & Telegraph Corp. Abstract:A simple mechanical connector for joining plastic coated optical fibers provides means for stripping the plastic from the fibers and for automatically aligning the fiber cores. The connector houses three equidistantly spaced teeth protruding from the inner surface of the connector. Inserting a plastic coated fiber within the connector causes the plastic material to be displaced by the teeth and causes the fiber to become precisely centered within the connector. When the connector contains teeth members at both ends of the connector a pair of optical fibers can become automatically aligned by inserting one of the fibers into each end of the connector. Representative Figure: Family DetailsGoogle Patents
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Publication:	8/15
Publication No:	US 4087156
Title:	Optical fiber transmission mixer and method of making same
Publication Type:	Grant
Publication Date:	May 2, 1978
Filing Date:	Nov 7, 1975
Inventors:	Charles K. Kao, James E. Goell
Original Assignee:	International Telephone & Telegraph Corporation
Abstract:	Methods and materials are disclosed for providing an optical fiber transmission mixer wherein the cladding material is removed from an intermediate region of a plurality of fibers and the exposed fiber cores are encapsulated in a matching or slightly higher refractive index material. The encapsulated intermediate region of the fibers is then enclosed in a low index sheath to prevent light from escaping from the mixer.
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Publication:	9/15
Publication No:	US 4081258
Title:	Method for using on line optic fiber loss monitor
Publication Type:	Grant
Publication Date:	Mar 28, 1978
Filing Date:	May 12, 1976
Inventors:	James E. Goell, Gary W. Bickel, Charles K. Kao, Mokhtar S. Maklad
Original Assignee:	International Telephone And Telegraph Corporation
Abstract:	A method and means is disclosed for continuously monitoring an optical fiber's attenuation or loss as it is being formed, which includes: a light source, which may be the heated fiber itself during drawing operations or an external source; passing the light through the fiber being produced; positioning the end of the fiber in a holder adjacent to a light detector, for example a photodiode with or without passing the transmitted light through a filter; detecting the light transmitted by the fiber from the light source; converting the detected light into an electrical equivalent signal; amplifying the signal if necessary and recording or observing the changes in the signal to determine an objective measure of the optical fiber's attenuating characteristic
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Publication:	10/15
Publication No:	US 4077701
Title:	Method and arrangements for dispersion equalization of optical fiber transmission lines
Publication Type:	Grant
Publication Date:	Mar 7, 1978
Filing Date:	Jun 2, 1976
Inventors:	Peter Dennis Steensma, Charles Kuen Kao
Original Assignee:	International Telephone And Telegraph Corporation
Abstract:	The dispersion effects in an optical fiber transmission line are equalized by producing a predetermined delay characteristic for each wavelength of an optical beam having a finite bandwidth which is the inverse of a given delay characteristic for each optical wavelength propagated through the transmission line. This is accomplished by launching shorter wavelength components of the optical beam at low angles with respect to the axis of the transmission line into the transmission line and launching longer wavelength components at high angles with respect to the axis of the transmission line into the transmission line. Two arrangements are disclosed to accomplish the above-mentioned launching technique. One arrangement includes a time of flight dependent annularly ruled transmission grating and the other arrangement includes passing a time of flight dependent moving acoustic wave through the optical beam.
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Publication:	11/15
Publication No:	US 4065280
Title:	Continuous process for manufacturing optical fibers
Publication Type:	Grant
Publication Date:	Dec 27, 1977
Filing Date:	Dec 16, 1976
Inventors:	Charles K. Kao, James E. Goell, Mokhtar S. Maklad
Original Assignee:	International Telephone And Telegraph Corporation
Abstract:	A continuous optical fiber manufacturing process utilizes the method of chemical vapor deposition of the glass forming materials within an R.F. excited glow discharge. The rapid deposition rate within the discharge provides a sufficient stream of glass material for winding into a finished fiber on a synchronous take-up mechanism. Alternate embodiments include an oxygen air stream to remove dust particles from the fiber surface and an in-line fluorine stream to terminate surface bonding and reduce moisture attack on fiber surfaces.
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Publication:	12/15
Publication No:	US 4057322
Title:	Precision surface optical fibers
Publication Type:	Grant
Publication Date:	Nov 8, 1977
Filing Date:	Nov 5, 1975
Inventors:	Charles K. Kao
Original Assignee:	International Telephone And Telegraph Corporation
Abstract:	Methods and apparatus are disclosed for forming a precision three-dimensional surface to clad optical fibers. One embodiment provides means for deforming the fiber end to conform to the geometry of the interstice formed between three tangential and parallel cylinders. The precision three-dimensional fiber end enables accurate low loss coupling between the fibers to be achieved through the accurate reference planes presented.
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Publication:	13/15
Publication No:	US 4047796
Title:	Precision optical fiber connector
Publication Type:	Grant
Publication Date:	Sep 13, 1977
Filing Date:	Sep 15, 1975
Inventors:	Charles Kuen Kao, Lozure Gene Wolfgang
Original Assignee:	International Telephone And Telegraph Corporation
Abstract:	Optical fiber ends are precisely aligned and coupled together in the interstice between a plurality of like contacting cylindrical rods. The rods are mounted along and around the fibers within an adjustable connector assembly. Means are provided for expanding the interstice to inset the fiber ends and for clamping the rods in position around the fibers. A plurality of connectors may be used to align a number of optical fibers enclosed in a common cable or bundle.
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Publication:	14/15
Publication No:	US 4017149
Title:	Multiple access fiber optical bus communication system
Publication Type:	Grant
Publication Date:	Apr 12, 1977
Filing Date:	Nov 17, 1975
Inventors:	Charles K. Kao
Original Assignee:	International Telephone And Telegraph Corporation
Abstract:	A multiple access fiber optical bus system having superior features as compared to the prior art is provided in which single fibers may be used as transmission lines in a closed loop system. A plurality of optical transmission mixers are provided, each of which mixes the inputs from one or more transmission lines to provide outputs to a multiplicity of transmission lines. Each of the mixers independently operates a plurality of transmission lines. Various degrees of reliability terminals are provided. A high reliability terminal has inputs from and outputs to the last one of the transmission lines on the output side of each of the independent mixers. A low reliability terminal has connections to only one of the independent mixers transmission lines. Any degree of reliability between the lowest and highest can be obtained depending upon the number of independent mixer loops to which such a terminal is connected.
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Publication:	15/15
Publication No:	US 3549233
Title:	Waveguide for electromagnetic waves
Publication Type:	Grant
Publication Date:	Dec 22, 1970
Filing Date:	Sep 20, 1967
Inventors:	Eaglesfield Charles Cecil, Kao Charles Kuen
Original Assignee:	Int Standard Electric Corp
Abstract:
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