Abstract: An Add/Drop circuit for use in optical wavelength-division multiplexed systems includes fiber coupled four-port polarized beamsplitters and fiber Bragg grating filters.

Abstract: A rail-to-rail driver amplifier circuit that utilizes complementary output transistors to fully utilize the available power supply voltage. The circuit includes an input pre-amplifying circuit for receiving the audio signal and for receiving electrical energy from a power supply having a first rail at a positive potential and a second rail at a negative potential to produce a pre-amplified output signal. The circuit further includes a first output driver circuit having a voltage gain limited current amplifier coupled to the first rail and to a first output terminal of the input pre-amplifying circuit and a second output driver circuit having a voltage gain limited current amplifier coupled to the second rail and to a second output terminal of the input pre-amplifying circuit.

Abstract: Certain material and objects can be characterized by a frequency-dependent absorption, dispersion, and reflection of terahertz transients in signals which pass illuminate the material or object. The present terahertz imaging system analyses that frequency dependence in the time-domain by collecting that transmitted signal propagating through the object and then processing the information contained in those signals for every point or "pixel" on that object. This is a non-invasive imaging technique that is capable of differentiating between different materials, chemical compositions, or environments.

Abstract: Low optical loss and simplified fabrication are achieved by a nonlinear reflector which incorporates one or more semiconductor quantum wells within an n half-wavelengths strain relief layer (where n is an odd integer greater than zero) that is formed on a standard semiconductor quarter wave stack reflector. Growth of the half-wavelength layer is controlled so that dislocations are formed in sufficient concentration at the interface region to act effectively as non-radiative recombination sources. After saturation, these recombination sources remove carriers in the quantum well before the next round trip of the optical pulse arrives in the laser cavity. The nonlinear reflector is suitable for laser modelocking at the high wavelengths associated with many currently contemplated telecommunications applications and provides, at such wavelengths, an intensity dependent response that permits it to be used for saturable absorption directly in a main oscillating cavity of a laser.

Abstract: A telephone ringing system in which one or more user-selected sound segments are received using the microphone portion of a telecommunications instrument, stored in digital or analog form, and audibly reproduced using the loudspeaker portion of the telecommunications instrument when a ring signal is detected to provide a distinctive, personalized indication of an incoming call.

Abstract: A circuit for maintaining the magnitude of a radio frequency (RF) signal at least one predetermined level employs a detection circuit coupled to an RF signal generator by a four port coupling device. In one embodiment of the present invention, an impedance inverter in series with a diode is connected between the load termination of the coupling device and ground. The series combination of the impedance inverter and diode approximates a short circuit as the output signal power approaches a predetermined low amplitude threshold and approximates an open circuit as the output signal power approaches a predetermined upper amplitude threshold so that gain is provided to signals received by the detection circuit below a first amplitude level and attenuation is provided to signals received by the detection circuit above a second amplitude level.

Abstract: A light source includes a light emitting diode and an optical fiber having a first end coupled to the output of the light emitting diode. A single or multiple transverse mode optical semiconductor amplifier has an input coupled to a second end of the optical fiber. The light source may be fabricated from discrete components or alternatively it may be fabricated as a monolithically integrated device.

Abstract: An optical communication system is disclosed including an all-optical device whose output modulated optical beam is locked to an input modulated optical beam. In a specific embodiment of the system, the device may be a self-electro-optic effect device (SEED), which is operated as an oscillator by means of an associated tank circuit. Such an embodiment permits recovery of a clock frequency from a bit stream which is input into the device. When the output of the device is directed into an optical decision element, an all-optical regenerator may be realized.

Abstract: A method for designing an integrated circuit having optical inputs and outputs includes the step of selecting an integrated circuit design which includes at least one circuit cell design for processing electric signals. The circuit cell design has a predetermined number of electric inputs and electric outputs. The integrated circuit design also includes a plurality of layers of metalization for providing electric coupling. After the electronic integrated circuit design is selected, a predetermined number of optical input devices are located on the circuit cell design in a first prearranged orientation. The predetermined number of optical input devices is no greater than the predetermined number of electric inputs to the circuit cell. Also after the electronic circuit design is selected, a predetermined number of optical output devices are located on the circuit cell design in a second prearranged orientation.

Abstract: An article of athletic footwear or legwear comprises a flexible interior member manipulable to receive at least a portion of a wearer's foot and a first pair of disk members coupled to opposed exterior surface portions of the flexible interior member and positionable over the lateral and medial sides of the ankle joint. Each disk member defines a substantially convex, outwardly facing exterior surface portion.The article, which may be an athletic shoe, ski boot, skate, or the like, further comprises an exterior assembly defining an interior cavity dimensioned and arranged to receive the flexible interior member while the interior member is worn on the foot of the wearer. A second pair of disk members are coupled to opposite interior surface portions of the exterior assembly within the cavity.

Abstract: A method of making a silicate optical waveguide structure for transforming an optical beam of a first modal spot size to a beam of a second modal spot size includes the step of selecting an irradiation energy which is at least partially absorbed by the cladding of the structure. A variable dosage of radiation is then provided along the length of the structure. The radiation has an energy equal to the selected irradiation energy so that a refractive index change of the cladding is greater than a refractive index change of the core.

Abstract: New media have been developed for china paints useful for painting or decorating porcelain bisque, ceramic and stoneware articles. These media, consisting of low surface tension glycols and water soluble polymers, enable the artisan to paint non-blotching surfaces, fine lines and details and multiple layers without a separate kiln firing between layers.

Abstract: A system and method for generating a signal having a reliable, fixed duration and/or delay as a function of relative, not absolute, device characteristics. That is to say, the time period of the generated signal is determined as a ratio of one device's operating characteristics to another device's operating characteristics. In particular, the invention provides a fixed time signal as a function of the relative values of two capacitive elements that have a known ratio of capacitance with respect to each other. The invention is particularly useful when implemented upon an integrated circuit, as standard fabrication techniques for such circuits allow relative device characteristics to be held to relatively tight tolerances.

Abstract: Spectral broadening over a large range using PM is achieved by a lightwave source without the need for a large phase modulation index and without expending a large amount of modulator RF drive power. In this lightwave source, a laser output signal is externally phase modulated by one or more modulation signals. The phase modulation employs one or more frequency drive signals (i.e., the modulation signals) each of whose amplitude is judiciously selected to produce an output spectrum having substantially equal spectral components over a predetermined range of frequencies. The predetermined frequency range is centered about the source frequency for the laser and resembles a comb. Each frequency drive signal is also selected to have a frequency (or frequency spacing from other drive signals) so that adjacent spectral components in the output spectrum of the modulated signal are produced with a frequency spacing which exceeds the SBS interaction bandwidth at the transmission wavelength of interest.

Abstract: The user interface in an automatic speech recognition (ASR) system is dynamically controlled, based upon the level of confidence in the results of the ASR process. In one embodiment, the system is arranged to distinguish error prone ASR interpretations from those likely to be correct, using a degree of confidence in the output of the ASR system determined as a function of the difference between the confidence in the "first choice" selected by the ASR system and the confidence in the "second choice" selected by the ASR system. In this embodiment, the user interface is arranged so that the explicit verification steps taken by the system as a result of uncertain information is different from the action taken when the confidence is high. In addition, different treatment can be provided based upon the "consequences" of misinterpretation as well as the historical performance of the system with respect to the specific user whose speech is being processed.

Abstract: An intelligent terminal (which can be a telephone, a facsimile machine, or similar device) is arranged so that (a) it can store information indicating when (e.g., date and time) a particular subscriber last was present at the terminal, and (b) the stored information can be retrieved from the terminal remotely, preferably without completing a conventional call to the terminal. A central processor contains, for each subscriber, a list of the intelligent terminals that have been pre-designated for use by that subscriber, and has the ability to query terminals on the list. In response to a call placed to the subscriber by dialing the subscriber's unique personal number, specific intelligent terminals on that subscriber's list are queried by the central processor to determine when the subscriber was last present at each terminal. The central processor then generates a control signal such that the call is then completed to the particular terminal that was most recently visited by the subscriber.

Abstract: A video conference system provides eye contact and a sense of presence to a plurality of conference participants located in respective remotely-sited conference rooms. Each conference room contains at least one video telephone or communications device that includes a video camera for generating video signals indicative of a sequence of local conferee image frames, and an image receiver for displaying image frames of at least one remote conferee. The image receiver, the video camera, and the eyes of the local conferee define a parallax angle. The video conference system further includes a frame generating system, responsive to the video signals, for analyzing local conferee image frames and generating a corresponding sequence of parallax-compensated frames. A signal indicative of each respective sequence of parallax-compensated frames is transmitted to a corresponding image receiver, whereby apparent eye contact is provided between each local conferee and a displayed image of a corresponding remote conferee.