Abstract: Embodiments of the invention provide an optical transmitter configured to transmit a data sequence over at least two spatial propagation modes through an optical transmission channel in a multi-mode optical fiber transmission system, the transmission system being associated with a predefined value of a mode-dependent loss, wherein the optical transmitter comprises: a forward error correcting code encoder (22) configured to encode said data sequence into a codeword vector by applying at least one error correcting code; a modulator (23) configured to determine a set of modulated symbols by applying a modulation scheme to said codeword vector; and a Space-Time encoder (24) configured to determine a codeword matrix by applying a Space-Time code to said set of modulated symbols.

Abstract: A test equipment module and method of communicating maintenance data in a cable system is disclosed. The module comprises a receiver, a measurement system, a pilot generator, and a signal encoder. The receiver receives downstream signals from a host communication network. The measurement system determines a maintenance parameter value associated with the downstream signals. The pilot generator generates a pilot within the downstream frequency band, and a signal encoder encodes the pilot with the maintenance parameter value. The pilot generator adds the encoded pilot to the downstream signals in the communication network, such that a cable modem in the network can receive the encoded pilot and generate a spectrum that includes the encoded pilot. A PNM server receives the spectrum from the cable modem and determines the maintenance parameter value from the spectrum.

Abstract: A mobile network device moves along a track rail structure of a ceiling-mounted track enclosure. The ceiling-mounted track enclosure further comprises a beam transmission cavity for accommodating a collimated light beam having a prescribed cross-sectional area and having been transmitted into the beam transmission cavity by a free space optical transmitter, without obstruction of the collimated light beam by the mobile network device along the track rail structure. The mobile network device receives, at a selected detection area within the cross-sectional area, a modulated light signal transmitted within the collimated light beam. The selected detection area is substantially smaller than the prescribed cross-sectional area and allocated exclusively to the mobile network device.

Abstract: A communication device of the disclosure includes: a first terminal that outputs a power supply voltage; a second terminal coupled directly or indirectly to the first terminal; a communication section that operates on a basis of the power supply voltage to communicate with a communication peer; and a communication controller that sets the communication section to be in an ON state or in an OFF state on a basis of a voltage on the second terminal.

Abstract: Provided are a wireless access system provided with a remote unit capable of handling a high-frequency region without being made complicated, and a control method for the same. A wireless access system according to the present invention is provided with: a center unit (1); and a remote unit (3) that converts a baseband signal generated by the center unit (1) into a high-frequency signal and emits the high-frequency signal from an antenna (12). The center unit (1) includes a 1-bit modulator (5) that converts the baseband signal into a 1-bit signal on the basis of a generated clock signal and outputs the 1-bit signal.

Abstract: A method includes receiving an optical signal through an optical link and determining a receiving power for the optical link. The method further includes comparing the receiving power for the optical link to a first receiving power threshold and transitioning a clock and data recovery circuit form a normal mode to a holdover mode when the receiving power is less than the first receiving power threshold. The clock and data recovery circuit, when operating in the holdover mode, configured to hold a recovered clock to a known-good clock frequency. When the receiving power for the optical link is greater than a second receiving power threshold, the method initiates a transition of the clock and data recovery circuit from the holdover mode to the normal mode and reacquires synchronization between the recovered clock and a current rate of the incoming data stream using the known-good clock frequency.

Abstract: A first apparatus comprises: a processor configured to generate a first synchronization message; a transmitter coupled to the processor and configured to transmit the first synchronization message to a second apparatus at a first wavelength; and a receiver coupled to the processor and configured to receive a second synchronization message from the second apparatus at a second wavelength and in response to the first synchronization message, the first wavelength and the second wavelength are based on a reduction of a latency difference between the second synchronization message and the first synchronization message, and the processor is further configured to calculate a TO between the first apparatus and the second apparatus based on the reduction.

Abstract: A packaged transmitter device includes a base member comprising a planar part mounted with a thermoelectric cooler, a transmitter, and a coupling lens assembly, and an assembling part connected to one side of the planar part. The device further includes a circuit board bended to have a first end region and a second end region being raised to a higher level. The first end region disposed on a top surface of the planar part includes multiple electrical connection patches respectively connected to the thermoelectric and the transmitter. The second end region includes an electrical port for external connection. Additionally, the device includes a cover member disposed over the planar part. Furthermore, the device includes a cylindrical member installed to the assembling part for enclosing an isolator aligned to the coupling lens assembly along its axis and connected to a fiber to couple optical signal from the transmitter to the fiber.

Abstract: An optical receiver (10) comprising: an input (12) arranged to receive a subcarrier multiplexing, SCM, optical signal (14) comprising an optical carrier and an optical subcarrier, each having a respective optical power; a carrier suppression element, CSE, (16) arranged to receive the SCM optical signal and having a rejection band that is tunable in frequency to partially suppress the optical carrier by a variable amount; an optical amplifier (18) having a variable gain and arranged to receive the SCM optical signal from the CSE and amplify the optical carrier and the optical subcarrier; a photoreceiver (20) arranged to receive the SCM optical signal from the amplifier; and a controller (24) arranged to cause frequency tuning of the rejection band and variation of the gain of the optical amplifier to adjust a ratio of the optical power of the optical carrier at the photoreceiver to the optical power of the optical subcarrier at the photoreceiver based on an indication of performance of the SCM optical signal.

Abstract: The present disclosure relates to a fiber optic network configuration having an optical network terminal located at a subscriber location. The fiber optic network configuration also includes a drop terminal located outside the subscriber location and a wireless transceiver located outside the subscriber location. The fiber optic network further includes a cabling arrangement including a first signal line that extends from the drop terminal to the optical network terminal, a second signal line that extends from the optical network terminal to the wireless transceiver, and a power line that extends from the optical network terminal to the wireless transceiver.

Abstract: A method and structure for signal propagation in a coherent optical receiver device. Asynchronous equalization helps to reduce complexity and power dissipation, and also improves the robustness of timing recovery. However, conventional devices using inverse interpolation filters ignore adaptation algorithms. The present invention provides for forward propagation and backward propagation. In the forward case, the filter input signal is forward propagated through a filter to the adaptation engine, while, in the backward case, the error signal is backward propagated through a filter to the asynchronous domain. Using such forward and backward propagation schemes reduces implementation complexity while providing optical device performance.

Abstract: A method and structure for tap centering in a coherent optical receiver device. The center of gravity (CG) of the filter coefficients can be used to evaluate a proper convergence of a time-domain adaptive equalizer. However, the computation of CG in a dual-polarization optical coherent receiver is difficult when a frequency domain (FD) adaptive equalizer is adopted. In this case, the implementation of several inverse fast-Fourier transform (IFFT) stages is required to back time domain impulse response. Here, examples of the present invention estimate CG directly from the FD equalizer taps and compensate for an error of convergence based off of the estimated CG. This estimation method and associated device architecture is able to achieve an excellent tradeoff between accuracy and complexity.

Abstract: A method includes receiving a first optical signal at a first communication terminal from a second communication terminal through a free space optical link and determining a receiving power for the optical link based on the first optical signal. The method further includes adjusting an output amplification at the first communication terminal based on the receiving power for the optical link. The output amplification is adjusted to provide a second optical signal with a minimum transmission power for maintaining the optical link. The method transmits the second optical signal from the first communication terminal to the second communication terminal through the optical link.

Abstract: Methods and systems for a photonic interposer are disclosed and may include receiving one or more continuous wave (CW) optical signals in a silicon photonic interposer from an external optical source, from an optical source assembly via optical fibers coupled to the silicon photonic interposer. A modulated optical signal may be generated by processing the received CW optical signals based on a first electrical signal received from the electronics die. A second electrical signal may be generated in the silicon photonic interposer based on the generated modulated optical signals, and may then be communicated to the electronics die via copper pillars. Optical signals may be communicated into and/or out of the silicon photonic interposer utilizing grating couplers. The electronics die may comprise one or more of: a processor core, a switch core, memory, or a router.

Abstract: Described herein is a ground based subsystem for inclusion in an optical gateway and for use in transmitting an optical feeder uplink beam to a satellite. The subsystem can include a wavelength-division multiplexing (WDM) multiplexer configured to receive optical data signals from optical network(s) external to the ground based optical gateway, and configured to combine the optical data signals into a wavelength division multiplexed optical signal. The subsystem can also include an optical amplifier to amplify the wavelength division multiplexed optical signal, and transmitter optics to receive the amplified wavelength division multiplexed optical signal and transmit an optical feeder uplink beam to the satellite in dependence thereon. In certain embodiments, the ground based optical gateway does not perform any modulation or demodulation of the optical data signals received from the optical network(s) external to the ground based optical gateway before they are provided to the WDM multiplexer.

Abstract: A method and structure for a coherent optical receiver device. Timing recovery (TR) is implemented after channel dispersion (i.e., chromatic dispersion (CD) and polarization mode dispersion (PMD)) compensation blocks. This architecture provides both improves performance and reduces power consumption of the device. Also, a TR loop is provided, enabling computing, by an error evaluation module, a first sampling phase error (SPE) and computing, by a timing phase information (TPI) module coupled to the error evaluation module, a second SPE from a plurality of CD equalizer taps PMD equalizer taps. The first and second SPE are combined into a total phase error (TPE) in a combining module, and the resulting TPE is filtered by a timing recovery (TR) filter coupled to an interpolated timing recovery (ITR) module and the combining module. The ITR module then synchronizes an input signal of the coherent optical receiver according to the TPE.

Abstract: An optical signal detecting apparatus and method. The optical signal detecting apparatus includes an optical demultiplexer configured to demultiplex an input optical signal into a first optical signal having a first band wavelength and a second optical signal having a second band wavelength, a first optical detector configured to detect the first optical signal, and a second optical detector configured to detect the second optical signal, and the optical demultiplexer, the first optical detector, and the second optical detector may be provided in a TO-CAN package.

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 application discloses an add/drop multiplexer, including a first line board and a tributary board, where the first line board includes at least a first interface and a second interface, the first interface is disposed between the tributary board and the first line board, and the second interface is disposed on a network side of the first line board; the first line board is configured to output a first signal received from a first link through the second interface; the first line board is configured to output a second signal received from the first link to the tributary board through the first interface; and the first line board is configured to receive a third signal from the tributary board through the first interface, and input the third signal into the first link. An inter-board interface on a link is effectively eliminated, thereby improving a link bandwidth of a device.

Abstract: Example embodiments of a time division duplex (TDD) Wavelength Division Multiplex Passive Optical Network (WDM PON) architecture using passive optical splitters are disclosed herein. The disclosed TDD WDM PON includes fixed wavelength optical transmitters in an Optical Line Termination system with tunable receiver colorless Optical Network Units (ONUs) that reuse the downstream CW light to carry upstream data. The same wavelength may be used for downstream and upstream transmissions on a single fiber in the ODN. In this architecture, the number of ONUs may be greater than the number of transmitters at the OLT, allowing for a highly scalable system with capacity for growth. An example embodiment of the disclosed system uses Arrayed Waveguide Grating (AWG) or WDM filters at the OLT and a passive optical splitter in the field.