Abstract: A system includes a switch and first and second servers. The switch receives first data and provides the first data to the first and second servers. The first server determines second data based on the first data and transmits the second data to the switch. The second server determines third data based on the first data in response to a faulty indication that the first server has failed to transmit the second data to the switch and transmits the third data to the switch. The switch transmits fourth data to the second server and a third server. The fourth data is either the second data or the third data. The second data is identical to the third data so as to confirm that one of the second data or the third data is transmitted to the third server when the first server has failed to transmit the second data.

Abstract: The invention provides a free space optical (FSO) communications terminal for a first telecommunications card or a backplane. The FSO terminal comprises a plurality of transmission interfaces. The FSO terminal further comprises a light signal generating unit adapted to generate a plurality of light signals. Each of the plurality of light signals carries the same information as the other one or more of the plurality of light signals and is arranged for transmission through a respective one of the plurality of transmission interfaces. Each of the plurality of light signals is at a different orthogonal mode from the other one or more of the plurality of light signals. The invention further provides a free space optical (FSO) communications terminal for a second telecommunications card or a backplane. The FSO terminal comprises a plurality of receive interfaces. Each of the plurality of receive interfaces adapted to receive a light signal carrying information.

Abstract: Optical switches and methods of switching include a first hybrid coupler configured to accept an input and to provide two branches. A phase tuner on a first branch includes a Mach-Zehnder phase shifter configured to shift a signal on the first branch by a selected phase. A loss compensator on a second branch is configured to match a loss incurred on the first branch. A second hybrid coupler is configured to recombine the two branches such that the phase shift generated by the phase tuner determines which output of the second hybrid coupler is used.

Abstract: A solid-state lighting fixture includes a first group of solid-state light elements, a second group of solid-state light elements, and a light control module. The first group of solid-state light elements is configured to emit visible light at a first wavelength. The second group of solid-state light elements is configured to emit light at a second wavelength, which is different from the first wavelength. The light control module is configured to modulate the light emitted from the first group of solid-state light elements and modulate the light emitted from the second group of solid-state light elements, respectively, such that the modulation pattern of the emitted light from each one of the first group of solid-state light elements and the second group of solid-state light elements communicates a first subset of data and a second subset of data, respectively, while being undetectable to the human eye.

Abstract: The present invention relates to an optical time domain reflectometer using, as a optical source, a polymer wavelength tunable laser which tunes the wavelength of an optical signal by using polymer grating. The optical time domain reflectometer of the present invention tunes the wavelength of a polymer wavelength tunable laser that outputs a constant optical signal and inspects cutting, reflection, and damage of an optical line by separating an optical signal returning from the optical line by an optical filter having a specific central wavelength. Since a optical source having a constant light intensity is used, the present invention has an effect of reducing the nonlinear effect generated in an optical line.

Abstract: A clock recovery method is provided. The method has the following operations: performing clock balance pre-filtering on an input time/frequency domain signal according to a self-adaptive balance coefficient input currently, to obtain a balance pre-filtering signal; according to the balance pre-filtering signal, acquiring a phase error of the input time/frequency domain signal; and performing phase adjustment on the input time/frequency domain signal according to the phase error, and outputting a new self-adaptive balance coefficient after self-adaptive balance processing is performed on the phase-adjusted time/frequency domain signal. A clock recovery device and system and a non-transitory computer-readable storage medium are also provided.

Abstract: A small form factor pluggable (“SFP”) transceiver for use in a communications network includes a transmitter adapted to be coupled to the network for supplying signals to the network, a receiver adapted to be coupled to the network for receiving signals from the network, and a programmable signal processing module coupled to the transmitter and the receiver and adapted to be programmed from a remote station coupled to the network. The module can be programmed to perform at least one service or management function on the network.

Abstract: Methods and systems for a distributed optical transmitter with local domain splitting is disclosed and may include, in an optical modulator integrated in a silicon photonics chip: receiving electrical signals, communicating the electrical signals to domain splitters along a length of waveguides of the optical modulator utilizing one or more delay lines, generating electrical signals in voltage domains utilizing the domain splitters, modulating received optical signals in the waveguides of the optical modulator by driving diodes with the electrical signals generated in the voltage domains, and generating a modulated output signal through interference of the modulated optical signal in the waveguides of the optical modulator. The delay lines may comprise one delay element per domain splitter, or may comprise a delay element per domain splitter for a first subset of the domain splitters and more than one delay element per domain splitter for a second subset of the domain splitters.

Abstract: Examples of information beamforming technology for visible light communication (VLC) systems are provided. A VLC system can include an array of light emitting diode (LED) elements that can emit omni-directional light and control circuitry that can control individual LED elements of the array to sinusoidally vary the intensity of the omni-directional light emitted from the individual LED elements. A data carrying light beam can be generated within an information beam region by constructively combining sinusoidal intensity variations of the emitted omni-directional light and uniform intensity light can be generated outside the information beam region by destructively combining the sinusoidal intensity variations. The VLC system can include an optical detector that can detect sinusoidal intensity variations of a data carrying light beam and generate an output signal corresponding to the sinusoidal intensity variations.

Abstract: A method for enhancing optical signal-to-noise ratio measuring precision by correcting spectral resolution is provided, which can obtain optical signal-to-noise ratio with enhanced measuring precision, by measuring actual power of broad spectrum signals in a certain bandwidth, determining the sum of the power of the sampling points for the broad spectrum signals in the bandwidth by using an optical spectrum analyzer, obtaining the corrected resolution of the optical spectrum analyzer, and replacing the setting resolution of the optical spectrum analyzer with the corrected resolution. The method can effectively solve the problem of large OSNR measuring error resulted from the difference between the setting resolution and the actual resolution of optical spectrum analyzer.

Abstract: Digital information can be carried on the fiber leg of an access network using binary modulation. Binary modulated data received at an O/E node can then be modulated onto an analog waveform using quadrature amplitude modulation or some other technique for modulating an analog waveform and transmitted over, for example, the coaxial leg of the network. The O/E node may also receive an analog signal, over the coaxial leg, modulated to carry upstream data from subscriber devices. The O/E node may demodulate the upstream signal to recover the upstream data and forward that upstream data over the fiber leg using a binary modulated optical signal.

Abstract: Disclosed are embodiments of an apparatus and method relating to an optical signal to noise ratio detection circuit, adopting an optical switch, a tunable optical filter, a photoelectric conversion module, a pilot-tone modulation signal conditioning module and a control module. After the photoelectric conversion module converts a to-be-detected optical signal to a voltage signal, the pilot-tone modulation signal conditioning module respectively amplifies an AC signal and a DC signal in the voltage signal, correspondingly converts the AC signal and the DC signal to two-way digital signals, determines a modulation depth of the pilot-tone modulation signal and a modulation depth of an ASE noise according to the two-way digital signals, and calculates an optical signal to noise ratio of the optical signal.

Abstract: A device for eliminating optical noise receives an optical signal, and includes a first filter which transmits light falling within a same wavelength range as the optical signal, so as to output a filtered signal including the optical signal and first background noise, a second filter which transmits light having a wavelength falling outside the wavelength range of the optical signal, so as to output second background noise, a converter which converts the filtered signal into a first electrical signal and converts the second background noise into a second electrical signal, and an operational unit which performs a mathematical operation on products respectively of the first and second electrical signals and first and second parameters, to result in an output signal.

Abstract: Provided is an analog optical transmission system using a dispersion management technique. The analog optical transmission system may include a digital unit (DU) pool including a plurality of DUs to transmit an optical signal; a plurality of radio units (RUs) to receive the optical signal; and one or more dispersion management apparatus to remove a signal distortion component caused by an interaction between a chirp and chromatic dispersion by compensating for the chromatic dispersion before the plurality of RUs receives the optical signal that is transmitted from the DU pool.

Abstract: This disclosure provides systems, methods, and apparatus for mitigating the effects of interference signals on optical signals received at a direct-detection optical receivers. The optical receivers are capable of attenuating interference noise signals resulting from the interference between a transmitted optical signal transmitted from a transmitter to the optical receiver and one or more additional signals received at the optical receiver. The interference can be due to multi-path interference or due to in-band interference. The receivers include a tunable filter for filtering the received optical signal to remove the interference. A frequency offset module processes the received optical signal to determine a frequency offset indicative of the difference between the carrier frequencies of a modulated optical signal and an interference optical signal.

Abstract: A central node for digital subscriber line access multiplex.

Abstract: Disclosed are a visible light communication system and a visible light communication method. In this system, a signal transmitter sends a visible light signal, and a signal light receiver capture an image of the visible light signal to recover the visible light signal according to the captured image. The signal receiver includes an image capturing module, an image processing module and a signal recovery module. The method includes: capturing an image of a visible light signal; processing the captured image of the visible light signal; determining whether there is a complete packet according to the processed image; if yes, directly recovering the visible light signal according to the processed image; but if no, executing a packet recovery process according to the processed image of the visible light signal, then obtaining the complete packet and recovering the visible light signal transmitted from the signal transmitter.

Abstract: The described implementations relate a Passive Optical Network (PON). In one implementation, the PON includes an Optical Network Unit (ONU) that has at least one transmitter subsystem component and an associated optical transmitter. The at least one transmitter subsystem component may be configured to be in an enabled state during a timeslot period assigned to the ONU for transmitting an upstream data burst and a disabled state after the timeslot ends.

Abstract: The availability of entangled quantum signals can improve distributed decision making. In particular, it can improve the efficiency of coordination and the ability to perform load balancing in high-speed wide-area networks, and other communication-constrained network environments. We include an application to high-frequency trading on geographically-separated financial markets, and we discuss load balancing in IT and electrical networks and also a battlefield scenario.

Abstract: A broadband communication network architecture with a train control network and a train serving network combined, is characterized by, comprising a trusted network and an untrusted network; the trusted network comprises a trusted carriage-level network element provided in each carriage, and in each of a front carriage and a last carriage, in addition to the trusted carriage-level network element, a trusted train-level network element is provided; the untrusted network comprises untrusted train-level network elements respectively provided in the front carriage and the last carriage; one trusted train-level network element communicates with one untrusted train-level network element via a security gateway, and several security gateways are redundant to each other.