Patents Examined by L. Van Beek
  • Patent number: 5121381
    Abstract: Disclosed is an optical switching apparatus comprising means for converting serial optical or electrical signals into parallel signals in a time division mode, first and second time division switch groups and a space division switch group for cross connecting the signal of the optical or electrical signals, and means for generating the edited optical or electrical signals as serial signals again.
    Type: Grant
    Filed: August 23, 1989
    Date of Patent: June 9, 1992
    Assignee: Hitachi, Ltd.
    Inventors: Yasushi Takahashi, Yoshitaka Takasaki
  • Patent number: 5081711
    Abstract: A system for communication between a computer and peripheral devices. The computer is made to generate long duration, synchronous, bi-phase binary coded electrical signals that can be shaped and amplified and then used to modulate a high frequency infrared light beam. Video and audio tape motion counts or electrical signal frequency counts can be read by the computer through the mouse port. Two pulse trains that change relative phase with a change in tape motion direction can be used to record motion counts and determine the direction of motion.
    Type: Grant
    Filed: November 8, 1988
    Date of Patent: January 14, 1992
    Inventor: James D. Rickman, Jr.
  • Patent number: 5062151
    Abstract: Personnel locating system for use in a facility having a plurality of rooms having doorways therein comprised of a plurality of portable transmitters. Each of the transmitters includes a battery and each generates an infrared signal. The system also comprises a plurality of fixed receivers positioned to cover different rooms at a facility. Each room has a receiver therein positioned to accept infrared radiation from a substantial portion of the volume of the room. Each receiver is capable of sensing and storing any of the infrared signals generated by the transmitters during any time the transmitters are located anywhere in the facility including when located within a room. The system also includes apparatus for polling the receivers to determine the location of any transmitter independent of the previous location of the transmitter.
    Type: Grant
    Filed: April 27, 1990
    Date of Patent: October 29, 1991
    Assignee: Fisher Berkeley Corporation
    Inventor: Robert T. Shipley
  • Patent number: 5058102
    Abstract: In optical communication systems for transmitting a plurality of broadband signals, particularly television signals, over an optical waveguide, the signals are modulated onto carriers of different frequencies, and the modulated carriers are transmitted as frequency-division-multiplex signals. The carrier frequencies lie in different frequency bands (B.sub.1, B.sub.2, B.sub.3) each of which is not more than one octave wide and which are spaced at least one octave apart. This makes it possible to adapt the system step by step to channel requirements using conventional, proven transmission equipment for the individual frequency bands.
    Type: Grant
    Filed: January 29, 1990
    Date of Patent: October 15, 1991
    Assignee: Alcatal N.V.
    Inventor: Rolf Heidemann
  • Patent number: 5040169
    Abstract: This invention describes a method of transmitting data through a passive central switching fabric, where data can be transmitted from any input port of the fabric to any output port of the fabric. The switching fabric has N multiplexors and N demultiplexors. The input ports of the demultiplexors are the input ports of the fabric, while the output ports of the multiplexors are the output ports of the fabric. The outputs of each demultiplexor lie in a horizontal plane, while the inputs of each multiplexor lie in a vertical plane. The outputs of the demultiplexors in the horizontal planes are butted against the inputs of the multiplexors so as to establish optical contact between the outputs of the demultiplexors and the inputs of the multiplexors. Modulated wavelengths are then demultiplexed and mutliplexed in such a fashion so as to allow data from any input port of the switching fabric to be transmitted to any output port of the switching fabric merely by modulating a corresponding one of N wavelengths.
    Type: Grant
    Filed: July 25, 1989
    Date of Patent: August 13, 1991
    Assignee: International Business Machines Corporation
    Inventors: Roch A. Guerin, Yeong-Chang Lien
  • Patent number: 5034944
    Abstract: Apparatus for controlling the transition of a number of lasers that are transmitting light to an optical bus from an off state to a sub-threshold bias state so as to minimize the transmission of light from lasers in the sub-threshold bias state. The apparatus places each laser in the sub-threshold bias state a predetermined time before it is to transmit data to the bus; and then, the apparatus places each laser in the off state after the data transmission has occurred. The lasers transmit in a sequential order onto the optical bus.
    Type: Grant
    Filed: October 31, 1988
    Date of Patent: July 23, 1991
    Assignee: AT&T Bell Laboratories
    Inventors: Gary J. Grimes, Lawrence J. Haas, Jon R. Sauer
  • Patent number: 5033112
    Abstract: A power and communication system for a building, and particularly a residential dwelling wherein there are provided a plurality of receptacles throughout the building, each connected by a cable to source, which may provide different voltages and either AC or DC and having a control interface for selectively switching the desired power to each cable individually. The control interface may also connect each cable to a selected signal transmission line, such as telephone, radio, TV, etc. The cable includes a pair of power conductors and a optical fiber which transmits to and receives from the control interface light signals informing the control interface what power or communication connection is required for a particular receptacle and possibly at the same time providing signal messages to each receptacle.
    Type: Grant
    Filed: December 11, 1987
    Date of Patent: July 16, 1991
    Assignee: Northern Telecom Limited
    Inventors: Geoffrey N. Bowling, John C. Goodwin
  • Patent number: 5031235
    Abstract: A system incorporating a pair of Mach-Zehnder modulators (164,166) for performing amplitude modulation of an optical carrier is disclosed. Each of the modulators is designed to suppress even order distortion products and develop third order distortion products of opposite sign and equal magnitude. The outputs of the two modulators are combined in a directional coupler (155) resulting in substantially suppressing second through fourth order distortion products.
    Type: Grant
    Filed: October 27, 1989
    Date of Patent: July 9, 1991
    Assignee: Hoechst Celanese Corp.
    Inventors: Donald Raskin, Kophu Chiang, James B. Stamatoff
  • Patent number: 5029240
    Abstract: The optical receiver has a photodiode (10) which is reverse biased by a voltage supply (14). The voltage supply provides a variable bias voltage determined by a control unit (16) and the photodiode is matched to the load (22) by an impedance matching circuit (12). The photodiode exhibits large capacitance changes over a range of bias voltages and may be implemented using a Schottky barrier or P.sup.+ N photodiode. By changing the bias voltage, the photodiode capacitance changes to vary the tuned frequency of the receiver. The matching circuit cancels the reactive component of the photodiode impedance and matches the resistive component to the load. The photodiode may have a doping profile in which an intrinsic or lightly doped region of width greater than the average photon penetration depth is located next to the junction. After the intrinsic region, the doping profile may be selected to achieve linear tuning. This doping profile gives linear tuning without sacrificing photodiode conversion efficiency.
    Type: Grant
    Filed: June 26, 1989
    Date of Patent: July 2, 1991
    Assignee: Hughes Aircraft Company
    Inventors: Michael de La Chapelle, Hui-Pin Hsu
  • Patent number: 5027435
    Abstract: One aspect of the invention is a Fabry-Perot cavity which has in part a waveguiding portion and in part a nonwaveguiding portion. In this manner, a cavity is constructed whose length would be too short to manipulate effectively if it were comprises exclusively of a waveguiding portion, and whose length might have unacceptable diffraction losses if it were comprised exclusively of a nonwaveguiding portion. In the inventive device the resonant wavelength can be adjusted by varying the length of either the gap or the waveguide or both. The device can be advantageously constructed and aligned using fiber coupling technology.
    Type: Grant
    Filed: January 27, 1989
    Date of Patent: June 25, 1991
    Assignee: AT&T Bell Laboratories
    Inventors: Andrew R. Chraplyvy, Patrick P. Iannone, Ivan P. Kaminow, Tingye Li, Julian Stone, Lawrence W. Stulz, Robert W. Tkach
  • Patent number: 5025487
    Abstract: A method of generating high power optical signals in the 1-100 GHz frequency range uses a frequency modulated semiconductor laser and an interferometer. This method is especially useful for microwave carrier frequency optical communications, distribution of microwave frequency local oscillator signals, and the generation of sinusoidal optical modulation at frequencies that cannot be reached by direct modulation in semiconductor lasers or with external module lasers.
    Type: Grant
    Filed: June 7, 1988
    Date of Patent: June 18, 1991
    Assignee: GTE Laboratories Incorporated
    Inventor: Elliot G. Eichen
  • Patent number: 5023948
    Abstract: A digital transmission system and method for coherent optical systems in which a source signal is frequency modulated by digital information and caused to be incident on a birefringent medium. Moudulation signals are produced having a polarization which is dependent on the frequency of the source signal. The information can be regenerated by processing only one of the modulation signals and thus only one need be transmitted. Further modulation signals may be transmitted to enable error checking at the receiver.
    Type: Grant
    Filed: March 1, 1989
    Date of Patent: June 11, 1991
    Assignee: British Telecommunications public limited company
    Inventor: David W. Smith
  • Patent number: 5023866
    Abstract: A radio frequency duplexer filter for a duplex transceiver is disclosed. To prevent spurious signals conducted by flyback responses of the transmit bandpass filter 103 from reaching the antenna (105), a band reject circuit consisting of third harmonic quarter-wave transmission line stubs (601 and 603) are advantegeously coupled to an output transmission line (107). Likewise, to prevent spurious signals conducted by flyback responses of the receive bandpass filter (113) from reaching the receiver (109), a band reject circuit consisting of third harmonic quarter-wave transmission line stubs (605 and 607) are advantageously coupled to an input transmission line (111).
    Type: Grant
    Filed: May 22, 1989
    Date of Patent: June 11, 1991
    Assignee: Motorola, Inc.
    Inventor: David M. De Muro
  • Patent number: 5023947
    Abstract: An optical equalization receiver for countering the effects of delay distortion is realized by utilizing dynamically controllable Fabry-Perot etalon structures. By dynamically adjusting the frequency response of an etalon that is in a feedback loop configuration, the associated delay characteristic of the etalon may be used to counter the effects of delay distortion, thereby allowing higher transmission rates and transmission distances to be achieved. In one exemplary embodiment, an optical receiver comprising a reflective Fabry-Perot etalon and a piezoelectric transducer is used in a feedback loop configuration wherein a feedback control circuit monitors an output signal from the etalon for generating a control signal representing the amount of delay needed to compensate for distortion in an optical signal incident on the etalon.
    Type: Grant
    Filed: November 1, 1989
    Date of Patent: June 11, 1991
    Assignee: AT&T Bell Laboratories
    Inventors: Leonard J. Cimini, Jr., Larry J. Greenstein, Adel A. M. Saleh
  • Patent number: 5023863
    Abstract: An optical switching system receives an optical input signal which is a wavelength-division multiplexed and time-division multiplexed signal. The optical input signal is divided into time-division multiplexed optical signals in different wavelength regions and transferred within an optical data bus after being subjected to a predetermined process including a frequency shift. The optical signals in the different wavelength regions are extracted from the optical data bus using optical bandpass filters, and multiplexed into an output optical signal which is a wavelength-division multiplexed and time-division multiplexed signal after being subjected to a predetermined process including a frequency shift.
    Type: Grant
    Filed: July 18, 1989
    Date of Patent: June 11, 1991
    Assignee: Fujitsu Limited
    Inventor: Shigefumi Masuda
  • Patent number: 5023942
    Abstract: A data transmission system, in which a plurality of repeater nodes are interconnected by optical fiber or electrical transmission links, which has a predetermined bypass path split ratio and does not require an automatic gain control circuit. Each node includes an electrical splitter at its input, an active branch including a receiver and a transmitter, and a passive branch which bypasses the active path. The active and passive branches are joined at the output of the node by an electrical combiner. By choosing the splitting ratio of the electrical splitters to have approximately a 70/30 split, with 70% going to the active branch and 30% going to the passive branch, a 10.sup.-9 bit error rate is readily achievable.
    Type: Grant
    Filed: June 26, 1987
    Date of Patent: June 11, 1991
    Assignee: Martin Marietta
    Inventor: Charles A. Goepel
  • Patent number: 5020152
    Abstract: A fault-tolerant fiber optic coupler/repeater for use in a terminal in a high speed digital, audio or video data transmission system has optical data input from one or a plurality of upstream terminals and sends optical data to one or a plurality of downstream terminals via fiber optic lines. The terminal includes one or more bypass lines and is connected to the bypass line of at least one upstream terminal. The terminal receives optical data signals from upstream terminals via a primary line and one or more bypass lines which bypass one or more of the upstream terminals. The terminal includes a logic device which analyzes the signals received by the terminal via the primary line and via the bypass line and analyzes or compares these signals to preset values. The logic device selects the signal having characteristics closest to the preset values and rejects the other signals.
    Type: Grant
    Filed: May 30, 1989
    Date of Patent: May 28, 1991
    Inventor: Andrew S. Glista, Jr.
  • Patent number: 5018130
    Abstract: In an optical packet switching system, a plurality of first wavelength tunable devices are connected respectively to incoming line terminals. In response to an incoming signal at the associated incoming line terminal, each of the first wavelength tunable devices generates an optical packet of a particular wavelength determined by a first wavelength selection signal supplied from a controller. In one embodiment, packets from the first wavelength tunable devices are switched through one or more paths set up by an optical space division switch to one of a plurality of optical buffers. Second wavelength tunable devices are respectively coupled to the outputs of the optical buffers for detecting a packet of a desired wavelength in response to a second wavelength selection signal from the controller and applying the detected packet to one of outgoing line terminals.
    Type: Grant
    Filed: June 22, 1989
    Date of Patent: May 21, 1991
    Assignee: NEC Corporation
    Inventors: Syuji Suzuki, Hiroshi Suzuki
  • Patent number: 5018131
    Abstract: A switch (10) which uses optical signals propagating through an air media is disclosed. Transmitters (14a-14n) radiate light along projection openings (40) through a solid, opaque housing (12). The projection openings (40) parallel each other and substantially reside in a lower plane (32) within the housing (12). Periscopic plugs (30) reflect such light upward along an intermediate direction (38) within the plugs (30) and out from the plugs (30) into incidence openings (42). The incidence openings (42) parallel each other and substantially reside in an upper plane (34) within the housing (12). Optical receivers (16a-16n) receive light propagating in the incidence openings (42). The incidence openings (42) reside substantially perpendicular to the projection openings (40).
    Type: Grant
    Filed: February 28, 1989
    Date of Patent: May 21, 1991
    Assignee: DSC Communications Corporation
    Inventors: Govind Shah, Peter A. Basile, Ralph H. Carmen, Stephen A. Deschaine
  • Patent number: 5016242
    Abstract: A method for generating a large number of stable microwave frequency components for wideband lightwave distribution networks is shown. A single oscillator is used at a transmitter to provide all of the required subcarriers. The subcarriers are modulated by high data rate channels and then multiplexed for transmission over a fiber optic line. At a receiver, all of the tuning frequencies required for channel selection are generated by a single oscillator.
    Type: Grant
    Filed: November 1, 1988
    Date of Patent: May 14, 1991
    Assignee: GTE Laboratories Incorporated
    Inventor: Douglas D. Tang