Abstract: A method is provided for assessing the quality of an optical transmitter and/or its interoperability with a receiver. The method includes obtaining an optical signal output by an optical transmitter and performing coherent optical-to-electrical detection of the optical signal to produce an in-phase receive signal and a quadrature receive signal. The method further includes a computing device emulating a worst-case configuration of an optical fiber with which the optical transmitter is to be used, based on the in-phase receive signal and the quadrature receive signal to produce a noise contribution associated with the worst-case characteristics of the optical fiber and determining a figure of merit of the optical transmitter based on the noise contribution.

Abstract: A system and method for high speed communication are provided. The system comprises a laser-based system for communication, the system comprising: an acquisition module configured to acquire and characterize a plurality of laser beams; a tracking module configured to track the acquired laser beams, the tracking module comprising: a beaconing feedback and beam divergence mechanism configured to control a beam and detect a beam; an adaptive learning unit configured to implement an adaptive learning detection algorithm to identify and track a unique optical signature from at least one of the acquired laser beams; and a pointing module configured to point at least one laser beam towards a target based on the acquired laser beams.

Abstract: An apparatus includes an optical source of an optical wavelength carrier, an optical modulator to receive the optical wavelength carrier, and an optical data receiver. The optical data modulator is configured to produce, from the optical wavelength carrier, an optical signal to carry separate data on different first and second components thereof in individual modulation periods during data transmission and to carry a training sequence on one of the components during time slots for calibration. The first component is relatively phase offset from the second component in the optical signal. The optical data modulator alternates the one of the components between the first and second components over the time slots for calibration. The optical receiver is connected to receive a portion of the optical signal and to temporally interleave a measurement of a characteristic of the first component and a measurement of a characteristic of the second component over the time slots for calibration.

Abstract: Provided is a device, which is a transmission device that can improve performance, that includes: a light source; and a transmitter that generates a modulated signal based on an input signal and transmits the modulated signal from the light source as visible light by changing a luminance of the light source in accordance with the modulated signal. The transmitter includes, in the modulated signal, a plurality of items of information related to service set identifiers (SSIDs) of a plurality of mutually different access points in a wireless local area network (LAN), and transmits the modulated signal from the light source.

Abstract: An apparatus for generating a time-delayed product of two independent signals includes a fixed-wavelength laser. A first optical modulator is optically coupled to the fixed-wavelength laser and configured to modulate a fixed wavelength optical carrier with a first input signal of a set of input signals. The apparatus also includes a tunable laser. A second optical modulator is optically coupled to the tunable laser and configured to modulate a tunable optical carrier with a second input signal of the set of input signals. The apparatus also includes a dispersive element coupled to the second optical modulator, a first optical detector coupled to the dispersive element, a third optical modulator optically coupled to the first optical detector and the first optical modulator, an optical 90-degree hybrid element optically coupled to the third optical modulator, and a plurality of optical detectors optically coupled to the optical 90-degree hybrid element.

Abstract: An optical transmission system includes: a first optical transmitting unit for transmitting a first optical signal having a first wavelength; a second optical transmitting unit for transmitting a second optical signal having a second wavelength; an output adjustment unit for acquiring the first optical signal and the second optical signal, adjusting signal intensities of the acquired optical signals, and outputting the optical signals; a multiplexer for multiplexing the first optical signal and the second optical signal that have been subjected to signal intensity adjustment and outputting a multiplexed signal; an amplifier for amplifying the multiplexed signal; a first optical receiving unit for receiving the amplified first optical signal; and a second optical receiving unit for receiving the amplified second optical signal.

Abstract: A method for chromatic dispersion pre-compensation in an optical communication network includes (1) distorting an original modulated signal according to an inverse of a transmission function of the optical communication network, to generate a compensated signal, (2) modulating a magnitude of an optical signal in response to a magnitude of the compensated signal, and (3) modulating a phase of the optical signal, after modulating the magnitude of the optical signal, in response to a phase of the compensated signal.

Abstract: A cover for an electronic circuit package, including: a body having an opening extending therethrough; a first element located in the opening and having a surface continuing planar or rounded shapes of a surface of the cover; and a second element of connection of the first element to the body.

Abstract: An object to provide a submarine optical transmission apparatus capable of efficiently housing optical components and electric components. First component housing units can house either or both of an optical component and an electric component and are stacked in a Z-direction. A case can house the first component housing units and a longitudinal direction thereof is an X-direction. A heat dissipating member is disposed in the case and conducts heat generated in the first component housing units to the case.

Abstract: An example system includes a first network device having first circuitry. The first network device is configured to perform operations including receiving data to be transmitted to a second network device over an optical communications network, and transmitting first information and second information to the second device. The first information is indicative of the data, and is transmitted using a first communications link of the optical communications network and using a first subset of optical subcarriers. The second information is indicative of the data, and is transmitted using a second communications link of the optical communications network and using a second subset of optical subcarriers. The first subset of optical subcarriers is different from the second subset of optical subcarriers.

Abstract: A method for laser chirp precompensation includes modulating an amplitude of an optical signal, in response to an amplitude of one of (i) a chirp-compensated signal generated via distortion of an original modulated signal according to an inverse of a chirp-response function of a laser and (ii) a first signal derived from the chirp-compensated signal, to yield an amplitude-modulated optical signal. The method also includes modulating a phase of the amplitude-modulated optical signal in response to a phase of one of (i) the chirp-compensated signal and (ii) a second signal derived from the chirp-compensated signal to yield a chirp-compensated optical signal.

Abstract: Embodiments relate to a local free space optical (FSO) terminal that transmits and receives optical beams. The FSO terminal includes a fore optic and a dispersive optical component. A receive (Rx) optical beam from a remote FSO terminal is received and focused by the fore optic to a Rx spot at a focal plane of the fore optic. A transmit (Tx) optical beam with a different wavelength forms a Tx spot at the focal plane and is collimated and projected by the fore optic to the remote FSO terminal. The dispersive optical component is positioned along optical paths of both the Rx beam and the Tx beam. Among other advantages, a wavelength dependence of the dispersive optical component laterally separates the Rx spot and the Tx spot at the focal plane.

Abstract: An optical transmission/reception unit includes a carrier rotatable around an axis of rotation, an optical receiver arranged at the carrier on the axis of rotation so as to receive an optical reception signal from a first direction, an optical transmitter arranged at the carrier adjacent to the optical receiver so as to emit an optical transmission signal in a second direction, and a transmission/reception optic arranged at the carrier on the axis of rotation above the optical receiver, wherein the transmission/reception optic includes a reception optic and a transmission optic arranged in the reception optic, wherein the reception optic is configured to guide the optical reception signal striking the transmission/reception optic towards the optical receiver on the axis of rotation, and wherein the transmission optic is configured to displace onto the axis of rotation the optical transmission signal emitted by the optical transmitter.

Abstract: In a distribution matching circuit, output data of a plurality of LUTs forming a hierarchical tree structure sequentially designates a combination of signal point groups in a signal space managed by an LUT in an immediately lower level, and signal point information after distribution matching is output for each LUT in the lowermost level.

Abstract: An optical transmitter, having an encoder and modulator, transmits a data signal. The encoder maps information bits of the data signal to a symbol in eight-dimensional (8D) constellation space spanned by vectors IXT1, QXT1, IYT1, QYT1, IXT2, QXT2, IYT2, QYT2, wherein I and Q are in-phase and quadrature components of an optical carrier, X and Y are orthogonal polarizations of the optical carrier, and T1 and T2 are two consecutive transmission time slots, by selecting the symbol from a set of constellation points in the 8D space. The modulator uses the symbol in the two consecutive transmission time slots to modulate two carrier waves, and to transmit the two carrier waves over the orthogonal polarizations of the optical carrier. The set of constellation points do not include any constellation point with parallel Stokes vectors in the two consecutive transmission time slots but comprise constellation points with orthogonal Stokes vectors.

Abstract: A transmitter block, comprising an optical source, a modulator, a transmission circuit and a control circuit. The optical source has a laser providing an optical signal. The modulator is configured to encode data into the optical signal using an m-quadrature amplitude modulation format. The transmission circuit has circuitry to receive data to be encoded into the optical signal. The transmission circuit has at least one drive circuit supplying driver signals to the modulator to cause the modulator to encode data into the optical signal using the m-quadrature amplitude modulation format. The control circuit supplies control signals to the transmission circuit to cause the transmission circuit to change the m-quadrature amplitude modulation format from a first m-quadrature amplitude modulation format to a second m-quadrature amplitude modulation format based upon predicted degradation of a link to receive modulated data from the modulator.

Abstract: A method of obtaining a measure of asymmetry between optical fibers of a forward and reverse paths is provided in order to synchronize clocks of optical nodes connected by asymmetrical optical fiber paths. The method includes receiving, at first and second arrival times, from a first optical network device, a first optical signal transmitted on a first optical fiber and a second optical signal transmitted on a second optical fiber, calculating a first time difference between the second arrival time and the first arrival time. The method includes determining a measure of asymmetry between the first optical fiber and the second optical fiber based on the first time difference and a second time difference between a first time of transmission by the first optical network device of the first optical signal and a second time of transmission by the first optical network device of the second optical signal.

Abstract: A network or system in which a hub or primary node may communicate with a plurality of leaf or secondary nodes. The hub node may operate or have a capacity greater than that of the leaf nodes. Accordingly, relatively inexpensive leaf nodes may be deployed to receive data carrying optical signals from, and supply data carrying optical signals to, the hub node. One or more connections may couple each leaf node to the hub node, whereby each connection may include one or more spans or segments of optical fibers, optical amplifiers, optical splitters/combiners, and optical add/drop multiplexer, for example. Optical subcarriers may be transmitted over such connections, each carrying a data stream. The subcarriers may be generated by a combination of a laser and a modulator, such that multiple lasers and modulators are not required, and costs may be reduced.

Abstract: A multi-core fiber includes: a plurality of cores; and a cladding portion formed around outer peripheries of the cores. Further, the cores each have a propagation characteristic conforming to any one of a plurality of standards for optical propagation characteristics, and of the cores, cores that are closest to each other conform to standards different from each other.

Abstract: The present invention provides a method for converting the topological charge of an orbital angular momentum mode of light to an opposite topological charge by applying the light to a spool of optical fiber having a bend radius R and length L. The length of the fiber used to form the spool is defined by ½ the bend-induced 2? walk-off length Ll,mb(2?). The length of the fiber L and the bend radius R of the spool may be adjusted to account for an ellipticity-induced 2? walk-off length Ll,m3(2?). Using the proportionality rules, Ll,mb(2?)?R2l and Ll,m3(2?)???l adjustments to account for ellipticity induced 2? walk-off length Ll,me(2?), or to account for a change in the bend radius ?R of the spool can be easily determined.