Switching Type Patents (Class 250/214LS)
  • Patent number: 6128110
    Abstract: A programmable optical logic gate for performing a selected function from the group including ALWAYS, NEVER, and logical OR, AND, NAND, NOR, XNOR, and XOR includes an optical logic circuit for receiving a first optical operand signal and a second optical operand signal and for performing a logic function on the first and second operand signals to produce an output signal, and further includes an optical logic function selection circuit coupled to the logic circuit for receiving logic function control signals and for selecting a logic function performed by the logic circuit on the first and second optical operand signals.
    Type: Grant
    Filed: November 18, 1996
    Date of Patent: October 3, 2000
    Inventor: Jeffrey A. Bulow
  • Patent number: 6078111
    Abstract: An optoelectronic switch for switching an input signal comprises two PIN des connected in series with opposed polarity, an input signal choke connected to the PIN diodes for presenting a high impedance to the input signal and a low impedance to a PIN diode bias, and a photovoltaic cell connected to the PIN diodes and the input signal choke for generating the PIN diode bias to switch the PIN diodes between a substantially conductive state while the photovoltaic cell receives optical energy from a light source and a substantially non-conductive state while the photovoltaic cell does not receive optical energy from the light source.
    Type: Grant
    Filed: December 23, 1997
    Date of Patent: June 20, 2000
    Assignee: The United States of America as represented by the Secretary of the Navy
    Inventors: Chen-Kuo Sun, Ching T. Chang, Richard Nguyen, Donald J. Albares
  • Patent number: 6075251
    Abstract: The present invention relates to a transmission method and device for efficient compression of digital data. The invention uses an optoelectronic coupler to receive light signals from a light transmitter at two bandwidths. A modulated signal generator is coupled to the transmitter which coverts voltage phase data signals to light signals. The data signals are modulated with a plurality of master profiles and subprofiles with different cycle time variations. The optoelectronic coupler has a pair of photodiodes. Light filters disposed on both diodes allow either the first or second bandwidth of light to pass. Conductors electrically couple the anode of the each photodiode to the cathode of the other photodiode which produce the voltage phase signal. A signal receiver is connected to the coupler and decodes the voltage-phase signal.
    Type: Grant
    Filed: May 14, 1999
    Date of Patent: June 13, 2000
    Assignee: Alan Y. Chow
    Inventors: Alan Y. Chow, Vincent Y. Chow
  • Patent number: 6069365
    Abstract: An image processing system for capturing and compressing images into a digital format is disclosed. The system has an array of imaging pixel elements which consist of two photodiode detectors. One photodiode detector is a capture detector while the other detector is a reference detector. The capture detector has an anode electrically coupled to the cathode of the reference detector. The cathode of the capture detector is electrically coupled to the anode of the reference detector. An image may be compared to a reference image detected by the reference detector. Different levels of light between the captured image and the reference image change the electrical output of the opsistor. Image compression is facilitated since only pixel elements which change from frame to frame need be stored. Additionally, a processing and compression circuit may use column and row scans to eliminate unchanged pixels and store only pixels with different light levels between images.
    Type: Grant
    Filed: May 14, 1999
    Date of Patent: May 30, 2000
    Assignee: Alan Y. Chow
    Inventors: Alan Y. Chow, Vincent Y. Chow
  • Patent number: 6028301
    Abstract: The present invention discloses a method for controlling a micro electro-mechanical system manufactured using micro-machining technology and verifying the state thereof and, more particularly, to a method for controlling the micro electro-mechanical system and verifying the state thereof using light so that the voltage applied to each MEMS is determined by the intensity of the light incident on two optical windows of the symmetric SEEDs respectively by attaching the symmetric SEEDs every MEMS to electrically connect one of the SEEDs to the MEMS in parallel, instead of a conventional method in which the voltage from the control circuit is applied directly to the MEMS via wires.
    Type: Grant
    Filed: November 12, 1997
    Date of Patent: February 22, 2000
    Assignee: Electronics and Telecommunications Research Institute
    Inventors: Kwang Joon Kim, Jong Hyun Lee
  • Patent number: 6020593
    Abstract: The present invention relates to a transmission method and device for efficient compression of digital data. The invention uses an optoelectronic coupler to receive light signals from a light transmitter at two bandwidths. A modulated signal generator is coupled to the transmitter which coverts voltage phase data signals to light signals. The data signals are modulated with a plurality of master profiles and subprofiles with different cycle time variations. The optoelectronic coupler has a pair of photodiodes. Light filters disposed on both diodes allow either the first or second bandwidth of light to pass. Conductors electrically couple the anode of the each photodiode to the cathode of the other photodiode which produce the voltage phase signal. A signal receiver is connected to the coupler and decodes the voltage-phase signal.
    Type: Grant
    Filed: November 25, 1997
    Date of Patent: February 1, 2000
    Assignee: Alan Y. Chow
    Inventors: Alan Y. Chow, Vincent Y. Chow
  • Patent number: 5969336
    Abstract: A radiation sensor means for detecting a radiation comprises a radiation sensor element outputting a current which is generated by the incident radiation power, a detection circuit detecting the current generated by the radiation sensor element, and a reset circuit connected to the radiation sensor element in such a way that, when said reset circuit is driven by a reset signal, the charge carriers produced by the incident radiation power recombine at a rate which is higher than the rate without the reset signal, the reset signal being adapted to be applied to said reset circuit by means of the detection circuit.
    Type: Grant
    Filed: November 10, 1997
    Date of Patent: October 19, 1999
    Assignee: Sarad Gesellschaft Fur Komplexe Leistungen Zur Sanierung Radiologisch Belasteter Objekte MbH
    Inventors: Thomas Streil, Roland Klinke
  • Patent number: 5949064
    Abstract: An image processing system for capturing and compressing images into a digital format is disclosed. The system has an array of imaging pixel elements which consist of two photodiode detectors (Opsistor). One photodiode detector is a capture detector while the other detector is a reference detector. The capture detector has an anode electrically coupled to the cathode of the reference detector. The cathode of the capture detector is electrically coupled to the anode of the reference detector. An image may be compared to a reference image detected by the reference detector. Different levels of light between the captured image and the reference image change the electrical output of the opsistor. Image compression is facilitated since only pixel elements which change from frame to frame need be stored. Additionally, a processing and compression circuit may use column and row scans to eliminate unchanged pixels and store only pixels with different light levels between images.
    Type: Grant
    Filed: November 25, 1997
    Date of Patent: September 7, 1999
    Assignee: Alan Y. Chow
    Inventors: Alan Y. Chow, Vincent Y. Chow
  • Patent number: 5920065
    Abstract: The optoelectronic switch of the present invention comprises two PIN diodes onnected in series with opposed polarity having their intrinsic regions coupled to a light source for maintaining both diodes in the conductive state while the light source is on and in the non-conductive state while the light source is off.
    Type: Grant
    Filed: November 14, 1997
    Date of Patent: July 6, 1999
    Assignee: The United States of America as represented by the Secretary of the Navy
    Inventors: Chen-Kuo Sun, Ching T. Chang, Donald J. Albares, Richard Nguyen
  • Patent number: 5910738
    Abstract: A semiconductor device includes a voltage-driven switching element having a cathode and an anode, in which a voltage is to be applied between the cathode and anode, a power-supply circuit connected between the cathode and anode of the voltage-driven switching element and comprising capacitors, resistors and a reverse current-low preventing diode, for generating an intermediate voltage, a charging switching element for charging a gate of the voltage-driven switching element, using the intermediate voltage generated by the power-supply circuit, a discharging switching element for discharging the gate of the voltage-driven switching element, and a photovoltaic element for generating a photovoltaic power to control to drive the charging switching element and the discharging switching element.
    Type: Grant
    Filed: April 5, 1996
    Date of Patent: June 8, 1999
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Takashi Shinohe, Masakazu Yamaguchi, Kimihiro Hoshi
  • Patent number: 5900624
    Abstract: An optical correlator for correlating incident optical signals is described. The correlator comprises a transmission line in close juxtaposition to a photoconductor. The photoconductor may be positioned within the transmission line. The transmission line and the photoconductor may be monolithically integrated on a substrate. The optical correlator has an electrical non-linear response to the incident optical signals that results from a voltage divider formed from the combination of the transmission line and the photoconductor. The electrical non-linear response is proportional to a second-order intensity autocorrelation function g.sup.(2) (.tau.). The response time of the electrical nonlinear response is less than the width of the narrowest pulse of the optical signals and may be less than twenty picoseconds.
    Type: Grant
    Filed: May 29, 1996
    Date of Patent: May 4, 1999
    Assignee: Massachusetts Institute of Technology
    Inventors: Simon Verghese, Elliott R. Brown, Qing Hu
  • Patent number: 5837995
    Abstract: A wavelength-portion controllable optoelectronic switch ("Opsistor") capable of rapid switch frequencies fabricated as a monolithic integrated circuit is disclosed. The Opsistor is comprised of two inverse parallel photodiodes in close proximity, preferably on a monolithic silicon substrate, such that the anode of one photodiode is electrically connected via a first conductor to the cathode of the second photodiode, and the cathode of the first photodiode is electrically connected via a second conductor to the anode of the second photodiode. The voltage-phase of the Opsistor is determined by the relative illumination to the Opsistor's two photodiodes and is rapidly switchable. As a receiving device for data signals, the Opsistor receives programming signals from a transmitter light source.
    Type: Grant
    Filed: November 25, 1996
    Date of Patent: November 17, 1998
    Assignee: Alan Y. Chow
    Inventors: Alan Y. Chow, Vincent Y. Chow
  • Patent number: 5831259
    Abstract: A high impedance electrooptical transducer, such as for use in an optical output sensor. The transducer includes an electrosensitive element that emits photoluminescence radiation when illuminated by an excitation radiation. The electrosensitive element includes conjugate photoluminescent oligomers. The photoluminescence efficiency of the conjugate oligomers varies in the presence of an electrical field.
    Type: Grant
    Filed: November 25, 1996
    Date of Patent: November 3, 1998
    Assignee: Commissariat A L'Energie Atomique
    Inventor: Fabrice Charra
  • Patent number: 5825019
    Abstract: A timing device which is associated with a light level sensor and which is arranged to provide a time-out signal to a relay after a predetermined time has elapsed following detection of a low light condition and initial energization of the relay. The device provides for synchronization of an initiation time T.sub.1 and, hence, a time-out signal generating time T.sub.2 with respect to a periodically occurring event time T.sub.3 (for example, sunset time) in order that the desired time of generating the time-out signal might be re-established following interruption of power to the device. Should loss of power occur, the last entered event time T.sub.3 is employed to synchronize the initiation time T.sub.1 and, hence, the signal generating time T.sub.2, when detection of a predetermined light level next occurs following re-establishment of power to the device.
    Type: Grant
    Filed: October 10, 1996
    Date of Patent: October 20, 1998
    Assignee: H.P.M. Industries Pty Limited
    Inventor: Peter C. Birrell
  • Patent number: 5821528
    Abstract: The present invention includes two photodiodes in parallel connected to some transistors and an adjustable current source. The photocurrent difference from the two photodiodes combines with the current form the current source to be a positive value. This current then charges a capacitor. An automatic comparator circuit detects voltage of the charging capacitor. The Q output of the RS flip-flop is low and the transistor is off to charge the capacitor if the voltage of the capacitor is below a preset value. The buffer output is at low voltage in this case; The Q output of the RS flip-flop is high and the transistor is on to force discharging of the capacitor and the buffer output is at high level when the capacitor voltage reaches a preset value. By repeating these conditions, frequency modulated output can be obtained. The frequency value is related to the two light intensities difference and the current source combined current. When light intensity varies, the frequency varies accordingly.
    Type: Grant
    Filed: December 10, 1996
    Date of Patent: October 13, 1998
    Assignee: National Science Council
    Inventors: Tai Shan Liao, Jui I. Tsai, Keh Shium Liu, Mang Ou Yang, Yung Fu Chen, Ming Li Chen
  • Patent number: 5804815
    Abstract: A high gain, optically triggered, photoconductive semiconductor switch (PCSS) implemented in GaAs as a reverse-biased pin structure with a passivation layer above the intrinsic GaAs substrate in the gap between the two electrodes of the device. The reverse-biased configuration in combination with the addition of the passivation layer greatly reduces surface current leakage that has been a problem for prior PCSS devices and enables employment of the much less expensive and more reliable DC charging systems instead of the pulsed charging systems that needed to be used with prior PCSS devices.
    Type: Grant
    Filed: July 5, 1996
    Date of Patent: September 8, 1998
    Assignee: Sandia Corporation
    Inventors: Guillermo M. Loubriel, Albert G. Baca, Fred J. Zutavern
  • Patent number: 5777318
    Abstract: A smart pixel array is disclosed wherein a single optical beam can be used to transmit information to and from each subarea or cell of the pixel array. An optical P-I-N diode with an intrinsic MQW region is present in each subarea, and the optical beam is oriented to impinge on the diode. A first transmission gate couples information to be transmitted to the diode during a transmit interval, and information received by the diode is coupled through a second transmission gate to a receiver circuit during a receive interval. A third transmission gate couples a reset potential to the diode during spacing intervals between the transmit and receive intervals.
    Type: Grant
    Filed: January 17, 1996
    Date of Patent: July 7, 1998
    Assignee: Lucent Technologies Inc.
    Inventors: Ashok V. Krishnamoorthy, David A. B. Miller
  • Patent number: 5770853
    Abstract: A pulse generator is provided with a photoconductor in which first to third transmission lines composed of conductive film are formed on a semi-insulating substrate and the transmission lines are separated by first and second narrow gaps, and provides short pulses from short electrical pulses generated on these transmission lines in accordance with short optical pulses irradiated upon each narrow gap. Semiconductor lasers effect the irradiation of short optical pulses upon the first and second narrow gaps. A delay is conferred upon short optical pulses irradiated upon one of the first and second narrow gaps such that pulse height of short electrical pulses generated on the first to third transmission lines is maximized.
    Type: Grant
    Filed: November 18, 1996
    Date of Patent: June 23, 1998
    Assignee: Advantest Corporation
    Inventors: Takeshi Konno, Hitoshi Ujiie
  • Patent number: 5770389
    Abstract: A device and method for quantitative determination of an analyte in a biological sample utilizes a non-transparent support medium for retaining a chromatogenic reaction product with the medium being exposed to a source of light for transmitting therethrough a scattered, uniform response light signal which is collected at a photosensitive device whereby the amount of the analyte is correlated to the intensity of the response light signal. The response light signal may be converted to a time-duration signal proportional to light intensity to facilitate the quantitative determination.
    Type: Grant
    Filed: February 14, 1996
    Date of Patent: June 23, 1998
    Assignee: Abbott Laboratories
    Inventors: Shan-Fun Ching, Joanell Veronica Hoijer, Donald Irvine Stimpson, Julian Gordon
  • Patent number: 5726441
    Abstract: By giving an attention to the fact that the difference in the transmittance of solar radiation in the visible light region is small for each type of glass, even though the type of window glass is changed, the sensitivity ratio .alpha. of a sensor element 43a in a solar sensor 43 is set to be from 0.8 to 5 so that it has a spectral sensitivity closer to the visible light region in comparison with a conventional solar sensor. By this, the variation in the deviation of the sensor outputs depending on the types of the window glass is eliminated. Thus, a target sensor output corresponding to the amount of solar radiation can be attained without being influenced by the types of the glass, even when the transmittance for the wavelengths of sun light changes depending on the types of the glass.
    Type: Grant
    Filed: June 18, 1996
    Date of Patent: March 10, 1998
    Assignee: Nippondenso Co., Ltd.
    Inventors: Katsuhiko Samukawa, Yuji Honda
  • Patent number: 5717627
    Abstract: The optical memory device of the present invention comprises a photodetector device which generates a current when light is incident thereon and a light-emitting device which is connected to the photodetector device in series so as to emit light upon receiving a supply of current from the photodetector device and feed back thus emitted light toward the photodetector device.
    Type: Grant
    Filed: January 30, 1997
    Date of Patent: February 10, 1998
    Assignee: Hamamatsu Photonics K.K.
    Inventor: Yoshihiko Mizushima
  • Patent number: 5666376
    Abstract: An electro-optical device includes a vertical cavity surface emitting laser, a heterojunction light emitting device and heterojunction phototransistor on a semiconductor substrate. Layers of the heterojuncticn phototransistor and the heterojunction light-emitting device are electrically and optically coupled so there is regenerative optical and electrical feedback between them. Layers of the heterojunction light-emitting devices are proton implanted to control the feedback. Plural such devices are electrically and optically coupled together to perform logic functions, such as EXCLUSIVE OR, in response to optical signals.
    Type: Grant
    Filed: May 9, 1996
    Date of Patent: September 9, 1997
    Assignee: University of New Mexico
    Inventor: Julian Cheng
  • Patent number: 5663555
    Abstract: An image information processing apparatus comprising a parallel connection circuit for parallelly connecting a plurality of photo-electric conversion elements, a combined signal read circuit for reading out a combined signal from the plurality of parallelly connected photo-electric conversion elements, an individual signal read circuit for reading out an independent individual signal of each of the plurality of photo-electric conversion elements, a photometry circuit connected to the combined signal read circuit and a distance measurement circuit connected to the individual signal read circuit.
    Type: Grant
    Filed: July 2, 1996
    Date of Patent: September 2, 1997
    Assignee: Canon Kabushiki Kaisha
    Inventors: Mamoru Miyawaki, Isamu Ueno
  • Patent number: 5650611
    Abstract: A light switching apparatus includes an optically non-linear etalon, a first optical part for applying a signal light of a linear polarization to the optically non-linear etalon, and a second optical part for applying a control light of a circular polarization or elliptical polarization to the optically non-linear etalon. The control light varies a refractive index of an optically non-linear substance of the optically non-linear etalon to thereby perform a switching operation on the signal light.
    Type: Grant
    Filed: August 14, 1995
    Date of Patent: July 22, 1997
    Assignee: Fujitsu Limited
    Inventors: Yuji Nishikawa, Atsushi Takeuchi, Shunichi Muto
  • Patent number: 5646395
    Abstract: Optical analog information processing capability is achieved by providing a SEED device configured to operate in a differential mode. This "differential SEED" utilizes pairs of input signal beams to represent bipolar analog data and to process those data in a linear fashion. The difference in the optical powers of the input signal beams is used to modulate the absorption of power supply beams in quantum well diodes, such that the difference in the absorbed powers in the quantum well diodes is proportional to the difference in the powers of the input signal beams. The differential SEED can be configured to perform various image processing operations on bipolar analog data, including, for example, image addition and subtraction, optical multiplication, and evaluating spatial derivatives.
    Type: Grant
    Filed: June 30, 1995
    Date of Patent: July 8, 1997
    Assignee: Lucent Technologies Inc.
    Inventor: David Andrew Barclay Miller
  • Patent number: 5644123
    Abstract: A means and method of controlling a plurality of energy beams with at least one of the plurality of beams. At least one first beam set produces special interference with at least one second beam set, at a first location(s), diverting energy from both beam sets to a second location(s), where energy does not appear from one . . . or either, of the inputs in the absence of interference. By selecting the timing, levels, phases, frequencies, and interconnection of multiple controllers, a multitude of useful energy beam circuits are able to be made . . . such as: gated amplifiers, cascaded amplifiers, gated oscillators, phase demodulators, active filters, inverters, inverted filters, limiters, threshold detectors . . .
    Type: Grant
    Filed: April 19, 1995
    Date of Patent: July 1, 1997
    Assignee: Rocky Mountain Research Center
    Inventor: John Norman Hait
  • Patent number: 5631458
    Abstract: In a range finder, a capacitor for light emission is charged by turning off first and second switching elements and turning on third and fourth switching elements before light is emitted from a light emitting diode. A sum of a charging voltage of the capacitor for light emission and the voltage of a direct current power source is applied to the light emitting diode by turning on the first and second switching elements and turning off the third and fourth switching elements when light is emitted from the light emitting diode. At this time, an operation of the second switching element is controlled with a constant electric current by a constant current control circuit constructed by a transistor, a resistor for current limitation, a diode, etc. so that an electric current flowing through the light emitting diode is constant and a light emitting amount of the light emitting diode becomes constant.
    Type: Grant
    Filed: November 3, 1995
    Date of Patent: May 20, 1997
    Assignee: Ricoh Company, Ltd.
    Inventors: Toshiaki Nakahira, Susumu Iguchi, Kazumasa Aoki, Yoshihiko Shimura
  • Patent number: 5623140
    Abstract: Disclosed is a nonbiased bistable optical device and a method for fabricating the device, which has a semi-insulating GaAs substrate; a lower mirror having a plurality of reflecting layers which are repeatedly formed on said substrate at least more than twelve times, each of said reflecting layers having a first reflecting film having a first refractive index on said substrate and a second reflecting film a second refractive index different from the first refractive index; a first contact layer formed on the lower mirror; a first buffer layer formed on the first contact layer; a multiple quantum well(MQW) having a plurality of shallow layers which are repeatedly formed, each of said shallow layers having a barrier and a shallow quantum well; a second buffer layer grown on said MQW; and a second contact layer formed on said second buffer layer. The device has an excellent bistablity even without an external applied voltage.
    Type: Grant
    Filed: May 25, 1995
    Date of Patent: April 22, 1997
    Assignee: Electronics and Telecommunications Research Institute
    Inventors: Young-Wan Choi, O-Kyun Kwon, El-Hang Lee
  • Patent number: 5591963
    Abstract: A photoelectric conversion device comprising, on a substrate, a photoelectric conversion element having in lamination, a first electrode layer, a first insulating layer for blocking carriers of first conduction type and second conduction type from passing therethrough, a photoelectric conversion semiconductor layer, a second insulating layer for blocking carriers of first conduction type and second conduction type from passing therethrough, and second electrode layers and a switch element having laminated a gate electrode layer, a third insulating layer, a semiconductor layer, an ohmic contact layer, a pair of first and second main electrode layers, and a wiring layer for electrically connecting first or second electrode layer of photoelectric conversion element to first main electrode layer of the switch element can be provided with high SN ratio and at lower cost without providing the injection blocking layer.
    Type: Grant
    Filed: August 8, 1995
    Date of Patent: January 7, 1997
    Assignee: Canon Kabushiki Kaisha
    Inventors: Shinichi Takeda, Hidemasa Mizutani, Noriyuki Kaifu, Isao Kobayashi
  • Patent number: 5543631
    Abstract: This invention describes a dual mode optical switching device comprising organic quantum well regions interfacing with inorganic semiconductors. Each mode generates excitons and a photocurrent in their respective quantum well regions in response to incident control beams of different wavelengths of light. The photocurrents in each mode independently modulate the transmission of the lower frequency signal beams. Multiple hybrid organic/inorganic quantum well optical devices can be crafted into optical logic gates by using light impulses in a manner that is analogous to the way electronic gates are used in electronic systems. These devices can also perform as optical switches and optical interconnects between electronic elements. Thus the processing units are electronic and the connections between them are optical, comprising optoelectronic system with higher data throughput that will exceed electronic systems.
    Type: Grant
    Filed: March 29, 1994
    Date of Patent: August 6, 1996
    Inventor: Lester Weinberger
  • Patent number: 5543627
    Abstract: A method for optically powering and controlling a hydraulic actuator in which the electrohydraulic servo valve is powered and controlled by a solar cell, with incident light at optimum level, but frequency-modulated at low amplitude, allowing optimum impedance matching to the servo valve solenoids. The signal is F.M. detected using a discriminator, which outputs are applied to the bases of two transistors in series with the electrohydraulic servo valve solenoids. The nearly constant output impedance of the solar cell or a follow-up amplifier allows optimum performance of the discriminator. The unique feature is the operation of the solar cell at a light level which is optimum for efficiency of the system.
    Type: Grant
    Filed: September 23, 1994
    Date of Patent: August 6, 1996
    Assignee: The Boeing Company
    Inventor: Raymond W. Huggins
  • Patent number: 5541443
    Abstract: A semiconductor optoelectronic device which can be used to perform the logical INVERTER or NOR operation. The device includes a surface-emitting laser 200 electrically coupled to a heterojunction phototransistor 240. When the total illumination intensity at the phototransistor is below a given threshold, the laser is in a lasing state; when the total illumination exceeds the threshold, the laser is in a non-lasing state. The phototransistor is operated at bias voltages below the threshold for avalanche effects.
    Type: Grant
    Filed: December 15, 1994
    Date of Patent: July 30, 1996
    Assignees: AT&T Corp., Bell Communications Research, Inc.
    Inventors: Yong H. Lee, Jong-In Song
  • Patent number: 5532498
    Abstract: A high sensitivity control circuit for a solid-state relay is disclosed for use in optically coupled solid state relay circuits having a light emitting diode. The control circuit reduces a loading effect of the turn-off circuit on a photodiode array allowing the photodiode array to operate the switching transistor to switch an input signal to a switching contact. A two stage CMOS transistor circuit acting as an amplifier is employed for high-speed switching. Deactivation of the light emitting diode reverse biases a sense photodiode to discharge the switching transistor to prevent switching of the input signal to the switching contact.
    Type: Grant
    Filed: December 6, 1994
    Date of Patent: July 2, 1996
    Assignee: AT&T Corp.
    Inventors: Dean M. Umberger, Craig B. Ziemer
  • Patent number: 5523555
    Abstract: A photodetector device includes a semiconductive conjugated polymer, such as PPV, arranged between first and second electrode layers having different work functions, a bias circuitry connected to apply a bias voltage between the first and second electrode layers, and a sensing circuitry connected to detect a photocurrent flowing between the first and second electrode layers across the polymer layer as a result of radiation incident on the polymer layer while the bias voltage is applied. The bias voltage is selected in relation to the thickness of the polymer layer.
    Type: Grant
    Filed: September 14, 1994
    Date of Patent: June 4, 1996
    Assignee: Cambridge Display Technology
    Inventors: Richard H. Friend, Andrew B. Holmes, Donal D. C. Bradley, Robert N. Marks
  • Patent number: 5508508
    Abstract: An apparatus for converting a bipolar optical signal to a unipolar optical signal includes first and second photodetectors electrically coupled in series for receiving the bipolar optical signal. An electro-absorption modulator such as a self-linearized modulator, for example, is electrically coupled to the photodetectors. The modulator serves to transmit therethrough a portion of the power of an optical beam in an amount proportional to the power of the bipolar optical signal to form a transmitted beam. A constant current source is provided for supplying a current that shifts the power of the optical beam transmitted through the modulator by a predetermined amount, thus forming the desired unipolar optical signal.
    Type: Grant
    Filed: July 8, 1994
    Date of Patent: April 16, 1996
    Assignee: AT&T Corp.
    Inventor: David A. B. Miller
  • Patent number: 5498865
    Abstract: A photodiode amplifier includes an input stage having a first pair of transistors connected as a differential pair to have a low input impedance and a current source connected into the input stage to bias the pair of transistors. A photodiode is connected into the input stage across the transistors so as to provide differential effect to current flowing through the transistors. By means of such connection, the photodiode is presented with low input impedance, its time constant is accordingly lowered, and the system response of the photodiode amplifier is extended into higher frequencies. The photodiode amplifier is of particular use in an illuminant discriminator capable of distinguishing a range of separate illuminants, including high efficiency fluorescent lighting within the passband of the photodiode amplifier.
    Type: Grant
    Filed: December 16, 1994
    Date of Patent: March 12, 1996
    Assignee: Eastman Kodak Company
    Inventors: Michael J. Gaboury, Todd A. Jackson
  • Patent number: 5483186
    Abstract: A drive circuit for increasing the voltage range applied across optical modulators in a transmitter stage of an optical communication system. The circuit comprises a first switch and a second switch connected thereto. The first switch is responsive to a first input signal and has a maximum voltage drop equal to a first reference voltage. The second switch is responsive to a second input signal and has a maximum voltage drop equal to a second reference voltage. A modulator is connected between the first and second switches so that, depending on the values of the first and second input signals, the maximum voltage drop across the modulator will be a value greater than either the first or the second reference voltage.
    Type: Grant
    Filed: May 5, 1994
    Date of Patent: January 9, 1996
    Assignee: AT&T Corp.
    Inventors: David A. B. Miller, Ted K. Woodward
  • Patent number: 5466925
    Abstract: A means, method and apparatus is disclosed for providing at least one phase-modulated output from at least one amplitude-modulated input, which is used to produced the logical AND and OR functions having phase modulated outputs. A constant level bias beam set of at least one wavelength of any wave-type energy is superimposed on at least one modulated input beam set having an energy sum out of phase with the bias beam set at at least one location. Energy in the resulting interference image is separated from said at least one location to produce at least one output. Input levels determine the function performed. When the input energy sum is greater than the bias beam set, the output changes phase. When they are equal, the output is zero, which is also used to produce the NAND function.
    Type: Grant
    Filed: March 27, 1995
    Date of Patent: November 14, 1995
    Assignee: Rocky Mountain Research Center
    Inventor: John N. Hait
  • Patent number: 5448393
    Abstract: An optical receiver apparatus and method for receiving optical signals and for generating output signals is disclosed. In particular, a photoconductor is illuminated with a preset beam before an input beam is incident on a detector to reset an input FET. An optical receiver according to the invention controls the voltage swings and the allowed voltages at the input stage, and can be monolithically integrated to allow uniform operation across a semiconductor chip and between circuits on different chips.
    Type: Grant
    Filed: December 9, 1993
    Date of Patent: September 5, 1995
    Assignee: AT&T Corp.
    Inventors: Anthony L. Lentine, David A. B. Miller
  • Patent number: 5434426
    Abstract: Disclosed herein is an optical interconnection device having a light source, a plurality of optical interconnecting elements, and a light-receiving element. The optical interconnecting elements are located on an output side of the light source. Each of the elements has first and second major surfaces and comprises an integral unit made of an optical semiconductor element and a grating lens having concentric annular grooves and concentric annular projections, and two electrodes formed on the first and second major surfaces, respectively. The optical semiconductor element and grating lens of each optical interconnecting element are formed on the first major surface, for emitting or receiving light. The light-receiving element is located on an output side of the optical interconnecting elements. The optical interconnecting elements are arranged at substantially regular intervals, each positioned such that the semiconductor element and the grating lens face to the same direction.
    Type: Grant
    Filed: September 10, 1993
    Date of Patent: July 18, 1995
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Hideto Furuyama, Hiroshi Hamasaki, Mitsuhiro Kushibe, Katsuji Kaminishi, Tamon Kobayashi, Keiji Takaoka
  • Patent number: 5410147
    Abstract: An optical communications system includes apparatus for interferometric signaling in which light signals are propagated from a first location so as to form at least one predetermined interference pattern at a second location remote from the first location and then the received light signals are demodulated at the second location. The apparatus includes a substantially coherent light source and a plurality of adjacent, substantially coplanar optical modulators in the path of the emitted light.
    Type: Grant
    Filed: August 20, 1992
    Date of Patent: April 25, 1995
    Assignee: General Electric Company
    Inventors: Nabeel A. Riza, John E. Hershey, Amer A. Hassan
  • Patent number: 5408087
    Abstract: The gain uniformity of sealed microchannel plate image intensifiers (MCPIs) is improved by selectively scrubbing the high gain sections with a controlled bright light source. Using the premise that ions returning to the cathode from the microchannel plate (MCP) damage the cathode and reduce its sensitivity, a HeNe laser beam light source is raster scanned across the cathode of a microchannel plate image intensifier (MCPI) tube. Cathode current is monitored and when it exceeds a preset threshold, the sweep rate is decreased 1000 times, giving 1000 times the exposure to cathode areas with sensitivity greater than the threshold. The threshold is set at the cathode current corresponding to the lowest sensitivity in the active cathode area so that sensitivity of the entire cathode is reduced to this level. This process reduces tube gain by between 10% and 30% in the high gain areas while gain reduction in low gain areas is negligible.
    Type: Grant
    Filed: September 14, 1993
    Date of Patent: April 18, 1995
    Assignee: The Regents of the University of California
    Inventor: Stanley W. Thomas
  • Patent number: 5389776
    Abstract: A complementary field-effect transistor (CFET) receiver apparatus and method for receiving optical signals and for generating output signals is disclosed. In particular, four input beams, two of which are unique, are utilized to turn two series-connected FETs on and off to generate the output signals. A CFET photo-receiver according to the invention operates in push-pull fashion to conserve electrical power, and can be realized as a monolithically integrated device using FET-SEED fabrication techniques.
    Type: Grant
    Filed: November 22, 1993
    Date of Patent: February 14, 1995
    Assignee: AT&T Corp.
    Inventor: Ted K. Woodward
  • Patent number: 5384457
    Abstract: Methods and devices are disclosed for selectively varying the load to a photodetector such as a phototransistor which forms part of a photosource/photodetector pair and for selectively using to advantage or compensating for the parasitic capacitance of the photodetector to permit reductions in power, conversion of fixed signal thresholds to software controlled digital hysteresis, automatic adjustment and compensation for unmatched photosources and associated photodetectors, and adjustment of fixed voltage thresholds.
    Type: Grant
    Filed: August 10, 1992
    Date of Patent: January 24, 1995
    Assignee: Logitech, Inc.
    Inventor: Rene Sommer
  • Patent number: 5376784
    Abstract: This invention describes a dual mode optical switching device comprising organic quantum well regions interfacing with inorganic semiconductors. Each mode generates excitons and a photocurrent in their respective quantum well regions in response to incident control beams of different wavelengths of light. The photocurrents in each mode independently modulate the transmission of the lower frequency signal beams. Multiple hybrid organic/inorganic quantum well optical devices can be crafted into optical logic gates by using light impulses in a manner that is analogous to the way electronic gates are used in electronic systems. These devices can also perform as optical switches and optical interconnects between electronic elements. Thus the processing units are electronic and the connections between them are optical, comprising an opeoelectric system with higher data throughput that will exceed electronic systems.
    Type: Grant
    Filed: June 17, 1993
    Date of Patent: December 27, 1994
    Inventor: Lester Weinberger
  • Patent number: 5329113
    Abstract: An optoelectronic switching node is disclosed wherein two input optical beams can be switched in the sense that they can be regenerated in either one of two output spatial locations in response to input control signals. Each one of the input optical beams is coupled to a resonant cavity detector which generates a current when its corresponding optical beam impinges on its resonant cavity. Output optical beams are regenerated by two inversion channel lasers each one of which has emitter, source and sub-collector terminals and is bistable in the sense that it can be switched on and off by currents delivered into and taken out of its source terminal. Heterojunction field effect transistors are used to selectively couple the currents generated by the resonant cavity detectors to the source terminals of the lasers in order to turn them on.
    Type: Grant
    Filed: June 10, 1993
    Date of Patent: July 12, 1994
    Assignee: AT&T Bell Laboratories
    Inventors: Geoffrey W. Taylor, Timothy A. Vang
  • Patent number: 5315105
    Abstract: An optical operational memory device comprises a light-emitting device, a first and second phototransistors, and a load resistor. The light-emitting device and the first phototransistor are connected electrically in series to form an optical bistable switch based on optical positive feedback. The second phototransistor is connected in parallel to the optical bistable switch, and the load resistor is connected in series to the optical bistable switch. The time constant given by the product of the current gain of the second phototransistor, the base-collector capacitance of the second phototransistor, and the resistance of the load resistor is larger than the period required for recombination of the excess majority carriers in the base of the first phototransistor. A single optical beam modulated with pulse signals is input to the first and the second phototransistors simultaneously.
    Type: Grant
    Filed: July 29, 1993
    Date of Patent: May 24, 1994
    Assignee: Matsushita Electric Industrial Co., Ltd.
    Inventors: Kenichi Matsuda, Jun Shibata
  • Patent number: 5311008
    Abstract: Enhanced optical information processing capability is achieved by providing a self-electrooptic effect device (SEED) which modulates one or more power supply beams to provide integer gain in an input optical signal. This "integer gain" SEED includes a predetermined number of quantum well diodes electrically connected in series with a current supply so that, at steady state, each quantum well diode conducts the same current and thus absorbs the same amount of optical power. An optical input signal is replicated by configuring the quantum well diodes such that each quantum well diode receives its own power supply beam. The optical input signal is amplified by configuring the quantum well diodes such that a single power supply beam passes through all of the quantum well diodes.
    Type: Grant
    Filed: December 28, 1992
    Date of Patent: May 10, 1994
    Assignee: AT&T Bell Laboratories
    Inventor: David A. B. Miller
  • Patent number: 5311009
    Abstract: In accordance with the invention, a quantum well device provides localized states for electrons having an energy E greater than the barrier height of the constituent quantum wells. The device comprises a confinement quantum well of width L.sub.w equal to an integer number n of deBroglie half wavelengths ##EQU1## and a plurality of adjacent quarter wavelength barriers and wells, each having a thickness equal to an odd number m of deBroglie quarter wavelengths. Constructive interference between the waves partially reflected by the interfaces between adjacent .lambda./4 barriers and .lambda./4 wells leads to the formation of a localized electron state at an energy E in the region of the confinement well. The device can be used in detectors and modulators employing transitions between a bound state within the well and the localized state above the well.
    Type: Grant
    Filed: July 31, 1992
    Date of Patent: May 10, 1994
    Assignee: AT&T Bell Laboratories
    Inventors: Federico Capasso, Alfred Y. Cho, Jerome Faist, Carlo Sirtori, Deborah L. Sivco
  • Patent number: 5288990
    Abstract: Optical analog information processing capability is achieved by providing a SEED device configured to operate in a differential mode. This "differential SEED" utilizes pairs of input signal beams to represent bipolar analog data and to process those data in a linear fashion. The difference in the optical powers of the input signal beams is used to modulate the absorption of power supply beams in quantum well diodes, such that the difference in the absorbed powers in the quantum well diodes is proportional to the difference in the powers of the input signal beams. The differential SEED can be configured to perform various image processing operations on bipolar analog data, including, for example, image addition and subtraction, optical multiplication, and evaluating spatial derivatives.
    Type: Grant
    Filed: December 28, 1992
    Date of Patent: February 22, 1994
    Assignee: AT&T Bell Laboratories
    Inventor: David A. B. Miller