Abstract: Embodiments relate to providing simultaneous digital and analog services in optical fiber-based distributed radio frequency (RF) antenna systems (DASs), and related components and methods. A multiplex switch unit associated with a head-end unit of a DAS can be configured to receive a plurality of analog and digital downlink signals from one or more sources, such as a service matrix unit, and to assign each downlink signal to be transmitted to one or more remote units of the DAS. In one example, when two or more downlink signals are assigned to be transmitted to the same remote unit, a wave division multiplexer/demultiplexer associated with the multiplex switch unit can be configured to wave division multiplex the component downlink signals into a combined downlink signal for remote side transmission and to demultiplex received combined uplink signals into their component uplink signals for head-end side transmission.

Abstract: A mobile terminal is provided. The mobile terminal includes a light emitter, a light receiver, a light fidelity (LiFi) controller coupled with the light emitter and the light receiver, and a time-of-flight (TOF) controller coupled with the light emitter and the light receiver. The LiFi controller is configured to control the light emitter to emit a signal and control the light receiver to receive another signal. The TOF controller is configured to control the light emitter to emit a measurement light and determine a measured distance by performing distance measurement according to a reflected light of the measurement light received by the light receiver.

Abstract: A data transmission system is provided in the invention. The data transmission system includes a transmitting device and a receiving device. The transmitting device encodes data into a color pattern, and displays the color pattern. The receiving device extracts the color pattern and decodes the color pattern to obtain the data.

Abstract: A measurement device for polarization-maintaining optical fiber spindle difference delay is provided. The measurement device comprises a polarization-maintaining fiber (PM) Sagnac interferometer, a signal generator, a microwave detector, a microprocessor. The PM Sagnac interferometer comprises a laser, a photoelectric modulator, and a PM fiber coupler that are connected in sequence. The PM Sagnac interferometer further comprises an optical fiber interface J1 and an optical fiber interface J2 arranged at the two output ends of the PM fiber coupler, a PM fiber to be measured located between the fiber interface J1 and the fiber interface J2, and a photodetector arranged at the other output end of the PM fiber coupler.

Abstract: A Wireless LAN (WLAN) Li-Fi transceiver includes a Wi-Fi device and an Analog Front-End (AFE). The Wi-Fi device is configured to produce a spatial stream carrying data, and to produce from the spatial stream In-phase and Quadrature (I/Q) signals for transmission over a radio channel having a predefined Radio Frequency (RF) band. The Analog Front-End (AFE) is configured to modify the I/Q signals, or modify operation of the Wi-Fi device, for producing a real Li-Fi signal in a predefined optical band, and to transmit the data carried by the spatial stream to a remote Li-Fi receiver by driving an optical emitter with the real Li-Fi signal.

Abstract: An apparatus for generating a set of spectral correlation coefficients of an input signal includes: a master laser configured to generate an optical frequency comb signal; a first optical modulator configured to modulate the optical frequency comb signal with an input signal to generate a plurality of spectral copies of the input signal; a dispersive element configured to delay the plurality of spectral copies of the input signal by a wavelength-dependent time delay; a second optical modulator configured to modulate the delayed plurality of spectral copies with a conjugate of the input signal; and an optical comb filter configured to integrate the conjugate modulated plurality of spectral copies of the input signal to generate a set of cyclic autocorrelation coefficients.

Abstract: The method of transmitting data includes encoding, at an optical line terminal, data to be transmitted over a plurality of wavelength channels; providing the encoded data to corresponding lasers as modulation inputs, to enable the lasers to generate optical signals representing the data; multiplexing the optical signals; and equalizing the multiplexed optical signals for transmission via an optical transmission link. The method of receiving data includes de-multiplexing, at an optical network unit, optical signals received from an optical transmission link; selecting, from the de-multiplexed optical signals, an optical signal corresponding to a particular wavelength channel; converting the selected optical signal into electric signals; and decoding the electric signal to determine the data.

Abstract: Consistent with the present disclosure, an encoder circuit is provided at a transmit side of an optical fiber link that maps an input sequence of bits of fixed length k a sequence of symbols of a codeword of length n, such that the symbols of the codeword define a predetermined transmission probability distribution. Preferably, each symbol of the codeword is generated during a corresponding clock cycle, such that after n clock cycles, a complete codeword corresponding to the input bit sequence is output. On a receive end of the link, a decoder is provided that outputs the k-bit sequence every n clock cycles. Accordingly, buffers need not be provided at the output of the encoder and the input of the decoder, such that processing of the input sequence, codewords, and output sequence may be achieved efficiently without large buffers and complicated circuitry. Moreover, the input sequence, with any binary alphabet may be matched to a desired output distribution with any arbitrary alphabet.

Abstract: Adaptive scheduling for periodic data traffic in an optical communications network for a wireless communications system (WCS) is disclosed. Herein, an optical line terminator (OLT) in an optical communications network is configured to dynamically adjust a scheduled start time(s) of a scheduled period(s) in a periodic schedule to help reduce a schedule misalignment to below a predefined threshold. More specifically, the OLT is configured to determine the schedule misalignment. Accordingly, the OLT can adjust the respective scheduled start time(s) of the scheduled period(s) based on a temporal step determined based on the determined schedule misalignment to reduce the schedule misalignment to below the predefined threshold.

Abstract: A digital receiver is configured to process a polarization multiplexed carrier from a communication network. The polarization multiplexed carrier includes a first polarization and a second polarization. The receiver includes a first lane for transporting a first input signal of the first polarization, a second lane for transporting a second input signal of the second polarization, a dynamic phase noise estimation unit disposed within the first lane and configured to determine a phase noise estimate of the first input signal, a first carrier phase recovery portion configured to remove carrier phase noise from the first polarization based on a combination of the first input signal and a function of the determined phase noise estimate, and a second carrier phase recovery portion configured to remove carrier phase noise from the second polarization based on a combination of the second input signal and the function of the determined phase noise estimate.

Abstract: The present invention is directed to techniques and systems for extension of unrepeatered submarine fiber links to provide an increase in reach of unrepeatered fiber transmission. Both single channel unrepeatered systems and multiple channel unrepeatered systems can be used. The multiple channel unrepeatered systems can further employ nonlinearity compensation. The present invention is also directed to methods of signal transmission using the unrepeatered systems.

Abstract: Embodiments are disclosed of methods performed at an optical transmitter, devices and computer-readable storage media. For example, the method includes performing a process to select a PAM value from a set of candidate PAM values based on currently transmitted training data bits, transmitted Pulse Amplitude Modulation (PAM) values corresponding to previously transmitted training data bits, and training data bits to be transmitted subsequently, the selected PAM value corresponding to the currently transmitted training data bits. The selected PAM value is transmitted to an optical receiver, and an indication as to whether the optical receiver correctly detects the currently transmitted training data bits is received from the optical receiver. Then, the process is updated at least in part based on the indication. The manner of performing neural network learning at an optical transmitter side to obtain an encoding strategy can maximize the channel allowable capacity.

Abstract: A passive optical network communication method, including receiving an Ethernet packet carrying an optical network unit identifier, determining a correspondence between the optical network unit identifier and an optical network unit type according to the optical network unit identifier, determining that an optical network unit that receives the Ethernet packet is a first type of optical network unit, where the optical network unit type includes the first and second type of optical network unit, and a packet receiving rate of the first type is different from that of the second type, determining a correspondence between the optical network unit type and a channel according to the first type, determining a channel corresponding to the first type, encapsulating the Ethernet packet into a gigabit-capable passive optical network encapsulation method (GEM) frame, and sending the GEM frame to the first type of optical network unit using the determined channel.

Abstract: A vehicle communication system includes a core module, a first terminal module, and a second terminal module. The core module is installed in a vehicle and includes a first switching hub, a second switching hub, and a core communication line bundle. The first and the second switching hubs relay the data. The core communication line bundle includes a core optical cable that propagates optical signals and a core electrical wire that conducts electrical signals. In the core communication line bundle, the core optical cable and the core electrical wire couple the first switching hub and the second switching hub for communication. In the core communication line bundle, the core optical cable has a larger communication traffic volume than that of the core electrical wire.

Abstract: In an example implementation according to aspects of the present disclosure, a method may include receiving, at an optical receiver of a first device, a transmission signal from an optical transmitter source of a second device. The method may include decoding the transmission signal to generate a pairing code, and using the pairing code to pair the first and second devices together for wireless communication. The method may include granting a level of access control of the first device to the second device via the wireless communication, wherein the level of access control is based on the pairing code.

Abstract: Methods and apparatus for interference cancelation in a radio frequency communications device are described. In various embodiments a signal to be transmitted in converted into an optical signal and processed using an optical filter assembly including one or more optical filters to generate an optical interference cancelation signal. The optical interference cancelation signal is converted into an analog radio frequency interference cancelation signal using an optical to electrical converter prior to the analog radio frequency interference cancelation signal being combined with a received signal to cancel interference, e.g., self interference. The optical filter assembly can include a large number of taps, e.g., 30, 50, 100 or more. Each tap may be implemented as a separate optical filter or series of optical filters. Delays and/or gain of the optical filters can be controlled dynamically based on channel estimates which may change due to changes in the environment and/or communications device position.

Abstract: Methods, systems, and apparatus, including computer programs encoded on computer storage media, for clock synchronizing an optical system and multiple leaf systems. In some implementations, an apparatus includes a receiver comprising: a local oscillator laser providing a local oscillator signal, a detector circuit operable to receive a first optical signal and detect first data carried by the first optical signal based on the local oscillator signal, a reference clock circuit supplying a clock signal, a digital signal processor (DSP) operable to receive the first data and supply a control signal to the reference clock circuit based on the first data, the reference clock circuit being operable to adjust the clock signal based on the control signal; and a transmitter operable to output a second optical signal carrying second data, the second data having an associated rate that is based on the clock signal.

Abstract: An active optical cable is disclosed. According to the present disclosure, there is provided an active optical cable, having no complicated structure by obviating the need for a separate monitoring photodetector as was used for a typical optical transceiver, increasing light output-current linearity to improve optical coupling efficiency, generating a library of transmission/reception-related electro-optical characteristics of both optical modules so as to enable light outputted from a light source included in an optical transmitter to maintain high linearity over a wide range of temperatures, thereby reducing power consumption, and being applicable to a multi-level PAM technique involving at least four (4) levels.

Abstract: Disclosed herein is wavelength-division multiplexing (WDM) and demultiplexing with signal entry and exit in a common routing surface to increase channel density. In particular, disclosed is a WDM assembly including one or more common ports and one or more channel sets, with each channel set including one or more channel ports. The WDM assembly includes a first routing surface with a first WDM passband and a second routing surface offset from the first routing surface. The second routing surface is configured to reflect at least one signal passed through the first routing surface back through the first routing surface at a laterally different location. The offset controls a pitch between reflected signals, while maintaining a sufficiently large surface area to ensure proper signal performance and/or structural integrity. Controlling pitch by offset provides higher density routing with smaller channel pitches and/or more channels in a decreased volume.

Abstract: An optical data transmitter comprising two or more serially connected optical modulators, each driven using a respective DAC. The digital signals applied to the individual DACs are produced using different respective subsets of the set of bitstreams representing the digital waveform or data stream to be transmitted, with the bitstream subsets being selected, e.g., such that (i) each of the individual DACs is able to support the digital resolution and sampling rate needed for properly handling the subset of bitstreams applied thereto and (ii) differences between average driving powers applied to different optical modulators are relatively small. In different embodiments, the two or more serially connected optical modulators can be arranged for generating optical communication signals of different modulation formats, e.g., PSK, ASK, PAM, IM, and QAM. Some embodiments can advantageously be used for generating optical communication signals employing constellations of relatively large sizes, e.g.