Abstract: Apparatus and method for digital signal constellation transformation are provided herein. In certain configurations, an integrated circuit includes an analog front-end that converts an analog signal vector representing an optical signal into a digital signal vector, and a digital signal processing circuit that processes the digital signal vector to recover data from the optical signal. The digital signal processing circuit generates signal data representing a signal constellation of the digital signal vector. The digital signal processing circuit includes an adaptive gain equalizer that compensates the signal data for distortion of the signal constellation arising from biasing errors of optical modulators used to transmit the optical signal.

Abstract: This disclosure relates to optical line system equipment, which enables wavelength addition for long haul transmission. The system is configured to prevent contention of wavelengths added into a multiplexer. For example, an optical wavelength combiner, such as a multiplexer, may include components that are configured to detect potential collisions between existing wavelengths and a newly added wavelength, and block the addition of the conflicting wavelength while alerting the operator.

Abstract: The systems, apparatuses and methods of the present invention set forth improvements to the problems of the current pairing or duplex paradigm, resulting in a dramatic increase in fiber transmission efficiency, accomplished explicitly by restructuring presently-aligned C-Band wavelengths into innovative DWDM transmit and receive formats, and through implementing photonic-wave changes, which directs Ethernet data flow onto new path adaptations. These improvements could reduce line haul expenses significantly, believed to reach a projected 50% less requirement/deployment of fiber strands. This saving would offer owner-operators substantial fiber strand cost reductions, affecting transportation rates of high-bandwidth digital payloads traversing over DWDM networks, and lower usage rates of cross-connections amid multiple equipment inter-exchanging throughout large data centers.

Abstract: Embodiments of the invention include methods and devices for determining a phase angle offset between a phase angle of a local oscillator relative to a phase angle of a signal input of a Device Under Test (DUT). Some embodiments include a laser source and an optical phase adjustor, which may be embodied by a loop stretcher structured to controllably stretch a length of fiber optic cable, driven by a phase adjust driver. In other embodiments the phase angle offset information is conveyed to an oscilloscope for internal compensation.

Abstract: A coded visible light receiver comprises: a sensor, a transform module, and an interference cancelling module. The sensor receives light comprising data modulated into the light according to a coding scheme. The transform module is configured to transform the data into a frequency domain representation, representing a band of a spectrum resulting from the data being modulated into the light according to the coding scheme. The interference cancelling module is configured to cancel interference occurring in the band of the data, by determining one or more components in the band that exceed a threshold signal strength and cancelling those components.

Abstract: Novel tools and techniques providing for the robust wireless distribution of communications signals from a provider to multiple customer premises. Certain embodiments comprise one or more modular communications apparatuses which are located near to customer premises. The modular communications apparatuses features an enclosure which is, at least in part, transparent to radio frequencies. A modular communications apparatus also typically includes one or more communications radios or transmitter/receiver devices within the enclosure. The apparatus also includes at least one and possibly more than one antenna located within the enclosure along with wire or cable-based signal output apparatus.

Abstract: An example apparatus includes a mode selective detector, a measurement module, a difference calculator and a threshold and alarm module. The mode selective detector detects a plurality of modes of a spatially multiplexed signal. The measurement module measures a parameter for the plurality of modes of the spatially multiplexed signal, wherein the parameter is a power or a signal to noise ratio (SNR). The difference calculator compares the measured parameter among a subset modes and/or among a known set of unperturbed parameters and determines a differential, the subset including at least one mode. The threshold and alarm module sets an alarm indicator when the differential is out of bounds.

Abstract: An apparatus comprising a first electrical driver configured to generate a first binary voltage signal according to first data, a second electrical driver configured to generate a second binary voltage signal according to second data, wherein the first data and the second data are different, and a first optical waveguide arm coupled to the first electrical driver and the second electrical driver, wherein the first optical waveguide arm is configured to shift a first phase of a first optical signal propagating along the first optical waveguide arm according to a first voltage difference between the first binary voltage signal and the second binary voltage signal to produce a first multi-level phase-shifted optical signal.

Abstract: An optical transmission apparatus for transmitting wavelength-multiplexed light, the optical transmission apparatus includes: an optical transmitter configured to transmit light of a third wavelength to be arranged between a first wavelength and a second wavelength adjacent to the third wavelength in the wavelength-multiplexed light, and a controller configured to control a bandwidth of the light of the third wavelength to be arranged in a first bandwidth narrower than a spacing between the first wavelength and the second wavelength.

Abstract: An optical IQ modulator (IQM) including two parallel Mach-Zehnder modulators (MZM1, MZM2) generates single sideband data signals. A control unit (18) generates additional optical single sideband pilot signals (PS1, PS2) positioned in a lower and a higher sideband respectively, and also further pilot signals (PS3, PS4) in both sidebands. A IQ modulator output signal (MOS) converted into electrical monitoring signals (MOS) and monitored. A control unit (18) selects control signals (CS12, CS3, CS4) and controls the IQ modulator via its bias ports (6, 7, 8) till the power transfer functions (PTF) of the Mach-Zehnder modulators (MZM1, MZM2) and the phase difference (??) between their output signals is optimized.

Abstract: Communication bottlenecks, particularly in the downlink direction, are a common problem for many CubeSat developers. As described herein, a CubeSat module for a CubeSat comprises an optical transmitter to transmit data to a remote terminal, a receiver to acquire an optical beacon from a remote terminal, and a fine-pointing module operably and directly coupleable to a coarse-pointing module of the CubeSat. The fine-pointing module is configured to point the optical transmitter toward the remote terminal with an accuracy range that overlaps with an accuracy range of the coarse-pointing module of the CubeSat so as to establish a communications link between the CubeSat and the remote terminal over a low-Earth-orbit (LEO) distance.

Abstract: Methods and system for transmitting data includes converting multiple optical beams to distinct respective spatial modes. Data is modulated onto each of the optical beams. The optical beams are combined into a single transmission beam. The transmission beam is launched onto a multimode optical fiber having an elliptical core.

Abstract: Methods, systems, and apparatus for automatically identifying rogue Optical Network Unit (ONU) are disclosed. In one aspect, an Optical Line Terminal (OLT) determines dark power on a fiber optic link over a period of time. For a given ONU, the OLT determines an optical power of high signals and an optical power of low signals received over the fiber optic link during a timeslot assigned to the given ONU, determines a modified optical power of the high signals and a modified optical power of the low signals based on differences between the optical power of the respective signals and the dark power, determines an extinction ratio based on a ratio of the modified optical power of the high signals relative to the modified optical power of the low signals, and identifies the given ONU as a rogue ONU when the extinction ratio is outside of a specified range.

Abstract: An optical access network comprises an optical network unit having a first port for connecting to a first optical link, a second port for connecting to a second optical link and an optical source. The optical source is arranged to generate a first optical signal, to transmit the first optical signal via the first port, to receive an optical seed signal via the first port and to amplify the optical seed signal. The optical seed signal has a narrower bandwidth compared to the first optical signal. A modulator is arranged to modulate the amplified optical seed signal with upstream data to form an upstream optical signal and to transmit the upstream optical signal via the second port. A polarisation modifier can modify polarisation of the first optical signal.

Abstract: A network, a Visible Light Communications controller (120), and a method relate to a network architecture splitting frame processing functionality between Light Fidelity Access Points (130) and the Visible Light Communications controller or a virtualized controller. In such configurations, the Light Fidelity Access Points are so-called thin devices that may be widely deployed through an infrastructure to concurrently provide illumination and network access via Visible Light Communications protocols such as IEEE 802.15.7 or variants thereof.

Abstract: Aspects of a method and system for high-speed, low-power optical communications are provided. In one embodiment, a system for optical communications comprises a digital-to-analog converter (DAC), a driver, and a transmit optical subsystem. The DAC is operable to receive a digital code of a plurality of digital codes and output an analog current signal having an analog current level of a plurality of analog current levels. The driver is operable to condition the analog current signal output from the digital-to-analog converter. The transmit optical subsystem is operable to generate an optical power signal from the conditioned analog current signal. A mapping between the plurality of digital codes and the plurality of analog current levels is dynamically controlled according to one or more characteristics of the optical power signal. The one or more characteristics comprise or a symbol amplitude sensitivity and/or a nonlinearity that may be temperature dependent.

Abstract: The present invention includes a light communication method and system wherein messages are transmitted via color code flashes. The light communication includes mechanisms for oversampling the color code flashes to enhance the accuracy of the method and system.

Abstract: There is provided an optical transmission device including: a generator configured to convert an electric signal into a plurality of parallel signals, modulate the plurality of parallel signals, shift center frequencies of spectra of the plurality of modulated parallel signals into different frequencies, so as to generate signals accommodated in a plurality of sub-channels each having different center frequencies, and generate a multiplexed signal by multiplexing the signals accommodated in the plurality of sub-channels; a transmitter configured to optical-modulate the multiplexed signal and transmit the optical-modulated signal to an optical reception device; and a controller configured to control a frequency spacing between adjacent sub-channels of the plurality of sub-channels, based on a monitoring result of reception characteristics of the signals accommodated in the plurality of sub-channels within the multiplexed signal in the optical reception device.

Abstract: Managing performance of an optical communications network may be facilitated by digital noise loading techniques. The digital noise loading techniques may include measuring a quality of a communication signal received at a coherent optical receiver, applying digital noise to the communication signal at the coherent optical receiver, and detecting a change in the quality of the communication signal at the coherent optical receiver in response to the application of the digital noise. Based on the change in the quality of the communication signal, an operating characteristic and/or a performance margin of the coherent optical receiver may be determined, prompting or facilitating further actions such as adjusting one or more operating parameters of the optical communications network and/or triggering an alert.

Abstract: A nonlinear compensation method and apparatus and a system in a multicarrier optical communication system where the method includes: determining a coefficient of a linear filter in nonlinear compensation according to an end-to-end channel linear response of the system; determining taps of a nonlinear compensation filter needing to be opened and coefficients of the taps according to a hardware compensation ability of the system and the coefficient of the linear filter; and compensating for a nonlinear damage of the system by using the selected coefficients of the nonlinear compensation filter. With the method, apparatus or the system provided by this application, very good compensation performance may be achieved in a range of power consumption of the multicarrier optical communication system by only opening and using few taps of the compensation filter.