Abstract: An optical receiver receives a photocurrent from a photosensor and uses a transimpedance element to convert the photocurrent into an input signal. Next, an amplifier amplifies the input signal to produce an amplified input signal. At the same time, a clock-recovery circuit generates a clock signal, which is used to clock the amplified input signal to produce a receiver output. During an initial-calibration operation, the clock-recovery circuit phase-aligns a locally generated reference signal with transitions in the amplified input voltage signal to produce the clock signal by: feeding the reference signal through a delay-locked loop to produce a set of equally spaced phases; using the set of equally spaced phases to sample a preamble in the amplified input voltage signal to detect a crossing point; choosing a corresponding phase from the set of equally spaced phases based on the crossing point; and using the chosen phase to produce the clock signal.

Abstract: A flow of packets is communicated through a data center. The data center includes multiple racks, where each rack includes multiple network devices. A group of packets of the flow is received onto an integrated circuit located in one of the network devices. The integrated circuit includes a neural network and a flow table. The neural network analyzes the group of packets and in response determines if it is likely that the flow has a particular characteristic. The neural network outputs a neural network output value that indicates if it is likely that the flow has a particular characteristic. The neural network output value, or a value derived from it, is included in a flow entry in the flow table on the integrated circuit. Packets of the flow subsequently received onto the integrated circuit are routed or otherwise processed according to the flow entry associated with the flow.

Abstract: Optical signaling is implemented by modulating visible light with variable pulse position modulation (VPPM). VPPM is a composite waveform and its optical signal includes a Start Frame Delimiter (SFD) which indicates start of optical signaling. To identify modulated lights, the duty cycle is periodically changed in the waveform to induce an AM envelope at a frequency higher than the response of the human eye. The signal is then sampled via a camera producing an alias frequency that produces noticeable blinking. Because the communication is asynchronous, the desired camera frame rate (fc) in relationship to the modulation bit rate timing clock (or symbol rate, fs) is only approximate. Consequently, a frequency offset develops between the camera frame rate (fc) and the symbol rate (fs) in transmission of long packets. The disclosed embodiments provide a detection algorithm, system and apparatus to provide clock offset tracking and correction.

Abstract: Systems and methods for optical narrowcasting are provided for transmitting various types of content. Optical narrowcasting content indicative of the presence of additional information along with identifying information may be transmitted. The additional information (which may include meaningful amounts of advertising information, media, or any other content) may also be transmitted as optical narrowcasting content. Elements of an optical narrowcasting system may include optical transmitters and optical receivers which can be configured to be operative at distances ranging from, e.g., 400 meters to 1200 meters. Moreover, the elements can be implemented on a miniaturized scale in conjunction with small, user devices such as smartphones, thereby also realizing optical ad-hoc networking, as well as interoperability with other types of data networks. Optically narrowcast content can be used to augment a real-world experience, enhance and/or spawn new forms of social-media and media content.

Abstract: Optical fiber-based wireless systems and related components and methods are disclosed. The systems support radio frequency (RF) communications with clients over optical fiber, including Radio-over-Fiber (RoF) communications. The systems may be provided as part of an indoor distributed antenna system to provide wireless communication services to clients inside a building or other facility. The communications can be distributed between a head end unit (HEU) that receives carrier signals from one or more service or carrier providers and converts the signals to RoF signals for distribution over optical fibers to end points, which may be remote antenna units (RAUs). In one embodiment, calibration of communication downlinks and communication uplinks is performed to compensate for signal strength losses in the system.

Abstract: A method of providing data using visible light communication (VLC) and a VLC system therefor is provided, the method for easy utilization, in a user terminal, of information provided by a lighting apparatus based on a position at which the lighting apparatus is provided.

Abstract: An optical coupling system to couple a collimated beam with a waveguide made of semiconductor materials is disclosed. The waveguide is implemented in an optical modulator and/or an optical hybrid, and has a core with a restricted cross section because of the enhanced refractive index of the semiconductor materials. The collimated beam is focused on the core by the two-lens system including first and second lenses. The first lens, having a focal length shorter than a focal length of the second lens, is first aligned with the core, then, the second lens is aligned with the core as compensating deviations of the first lens induced during the fixation thereof.

Abstract: An optical device, comprising an optical component, configured to produce optical amplification; a component configured to intermittently supply coherent light to said optical component; and a controller, configured to apply a time varying signal to said optical component such that a plurality of light pulses are emitted during each period of time that said coherent light is received, wherein the plurality of light pulses emitted during each period have a fixed phase relation.

Abstract: Aspects of the subject disclosure may include, for example, a transmission device that includes a transmitter that generates a first electromagnetic wave to convey data, the first electromagnetic wave having at least one carrier frequency and corresponding wavelength. A coupler couples the first electromagnetic wave to a transmission medium having at least one inner portion surrounded by a dielectric material, the dielectric material having an outer surface and a corresponding circumference, wherein the coupling of the first electromagnetic wave to the transmission medium forms a second electromagnetic wave that is guided to propagate along the outer surface of the dielectric material via at least one guided-wave mode that can include an asymmetric mode, wherein the at least one carrier frequency is within a microwave or millimeter-wave frequency band and wherein the at least one corresponding wavelength is less than the circumference of the transmission medium. Other embodiments are disclosed.

Abstract: A method and system for establishing a free space optical link that includes creating a first link between a first vehicle and a second vehicle and pointing a laser from the first vehicle to the second vehicle. The method includes steering the laser in a spiral pattern and recording a time at the first vehicle of each incremental position of the laser in a spiral pattern. The method includes detecting the laser at the second vehicle, recording the time of detection at the second vehicle, and steering the laser to the positions that coincide with the detection times of the second vehicle to establish an optical link between the first and second vehicles. The first link may be a RF link. The free space optical link may be created with a conformal panel having an RF array, an optical detecting aperture, and an optical beam directing aperture.

Abstract: Techniques are described for a device that includes an optical channel configured to transport an optical signal. The device further includes a magnetic material with low optical absorption through which a portion of the optical signal is configured to flow. The magnetic material is configured to receive an electrical signal that sets a magnetization state of the magnetic material. The magnetic material is further configured to modulate, based on the magnetization state, the portion of the optical signal flowing though the magnetic material.

Abstract: A apparatus is provided that includes a security system that protects a secured geographic area, a passive infrared (PIR) array associated with the security system, and a processor of the security system that detects one of a plurality of predetermined hand motions by an authorized user based upon a signal from the PIR array and causes the security system to execute a predetermined instruction associated with that one predetermined hand motion.

Abstract: A test apparatus and method for testing passive optical networks is provided. The test apparatus includes an optical circuit having an optical coupler for splitting off a portion of optical traffic. During testing of a passive optical network, the optical circuit is coupled into an optical path of the passive optical network. A bit stream corresponding to an activating procedure is captured and analyzed to extract identification information of the module that sent the bit stream.

Abstract: A transceiver for fiber optic communications.

Abstract: A cable reel can improve transfer of power and data between a static frame and a cable wound around a rotatable element. The cable reel can use torsional springs to store mechanical energy and also to electrically couple the cable to a node within the static frame. This electrical coupling can be used to pass power. The cable reel can use a data transfer apparatus to transfer data between the frame and the cable. This apparatus may comprise two capacitive plates that together form a capacitor, one connected to the frame and one connected to the rotatable element. Alternatively, this apparatus may comprise an optically isolated zone in which an optical transmitter may communicate data to an optical receiver over free-space optical communications. The data can be transferred without physical contact between the frame and rotatable element, even while the rotatable element may rotate relative to the static frame.

Abstract: A system for delivering optical power over an optical conduit includes at least one optical power source delivering multiple optical power forms, at least one of the optical power forms being a modulated optical power form. The system includes an optical power receiving device that is directly driven by the at least one modulated optical power form.

Abstract: The present disclosure relates to a hand-held voltmeter measuring a peak voltage of a high voltage pulse applied to an electric fence. The voltmeter includes a body case of which one side has an opening, a sensor case protruded from the opening of the body case, a voltage divider disposed over the inside and the outside of the sensor case for dividing the high voltage pulse into a low divided voltage, a peak detector for detecting the peak voltage of the divided voltage, a display unit for displaying the peak voltage, and an MCU for controlling the input and the output of the elements constituting the voltmeter. According to the present disclosure, an electric fence voltmeter that measures the peak voltage accurately without need to make a ground connection to the earth, and has a low risk of an electric shock during a measurement is provided.

Abstract: A receiver for fiber optic communications.

Abstract: An optical line terminal (OLT) comprises a target OLT channel termination (CT), and a source OLT CT in communication with the target OLT CT, wherein the source OLT CT is configured to exchange tuning messages with the target OLT CT to initiate upstream wavelength tuning of an optical network unit (ONU), wherein the source OLT CT is configured to transmit a tuning request to the ONU after the tuning messages have been exchanged and to receive a tuning acknowledgement message from the ONU indicating that the tuning request will be executed, wherein the source OLT CT is configured to transmit a broadcast notification message to all OLT CTs within the OLT, except for the source OLT CT, after receipt of the tuning acknowledge message from the ONU, and wherein the broadcast notification message includes a tuning time of the ONU.

Abstract: An optical filter comprising a first distributed Bragg reflector (DBR) layer, a second DBR layer, and an intrinsic semiconductor layer positioned between the first DBR layer and the second DBR layer, with the intrinsic semiconductor layer providing a passband wavelength for the optical filter based on a carrier density of the intrinsic semiconductor layer.