Abstract: Embodiments herein describe generating signals for stabilizing a frequency comb using a PIC that contains a two-segment supercontinuum generator waveguide (SGW). A first segment of the SGW is designed to spread the spectrum of the frequency comb so that a significant portion of the spectral intensity of the frequency comb is at double the original frequency of the frequency comb. A second segment of the SGW is designed to spread the spectrum of the frequency comb so that a significant portion of the spectral intensity of the frequency comb is at a frequency of a reference laser.

Abstract: Electronic device including a lighting device, capable of illuminating a room or the like; a photodetector; an ultra-wideband pulse transmitter; an ultra-wideband pulse receiver; a controller, connectable to the internet; where the controller is adapted for coding a signal and transmitting it to the lighting device and/or to the pulse transmitter, and for decoding a signal received by the photodetector or the pulse receiver; the lighting device is adapted to transmit the signal as a LiFi signal and the pulse transmitter is adapted to transmit the signal as a UWB signal.

Abstract: A fiber link system, method and device for masking signals on a fiber link system. The system includes sending a desired sequence of information in the form of a true signal that is typically intended to be transferred between legitimate users at both ends of a link. Sending chaff signals, or subterfuge signals, alongside the true signal to mask such legitimate signals in the fiber cable from intruders tapping into the fiber cable.

Abstract: In an embodiment, a communication method includes: performing a receiving method by a receiving device including a visible light camera module that is capable of capturing invisible light emitted by an invisible light signal emitter of a sending device. The receiving method includes: broadcasting a camera frame rate; capturing, by the visible light camera module, a plurality of frames at the camera frame rate, wherein each frame includes a corresponding area caused by a corresponding signal pulse of a portion of signal pulses, and the signal pulses are emitted by the invisible light signal emitter at a signal pulse rate substantially same as the camera frame rate; detecting the corresponding area in each frame; and labeling the corresponding area in each frame, to obtain a coding pattern corresponding to a signal pulse pattern, and decoding the coding pattern, to identify a data sequence.

Abstract: Disclosed are an optical-time-division-multiplexed transmission method and system using a simple sinusoidally modulated optical signal as an input pulse source. An optical-time-division-multiplexed transmission system comprises: an optical-time-division-multiplexed transmitter by applying a sinusoidal electrical signal, a first multi-level electrical PAM signal, and a second multi-level electrical PAM signal so as to generate an optical-time-division-multiplexed multi-level PAM signal; an optical detector for converting the transmitted optical-time-division-multiplexed PAM signal into an electrical signal; a time-division-demultiplexer for demultiplexing the detected electrical signal into two signals; a MIMO equalizer; and two decision elements for determining the levels of two demultiplexed signals obtained from the MIMO equalizer.

Abstract: A first optical transceiver includes a transmission signal processor that generates a multi-valued pulse amplitude modulation signal including a fixed bit pattern. The first optical transceiver includes an optical transmitter that transmits the multi-valued pulse amplitude modulation signal as an optical transmission signal. The first optical transceiver includes an optical receiver that receives an optical adjustment signal from a second optical transceiver to reproduce an adjustment signal from the optical adjustment signal. The first optical transceiver includes a first controller that controls the transmission signal processor based on a bit error rate included in the optical adjustment signal to adjust light power at each level of the optical transmission signal.

Abstract: A computation unit uses an assumed chromatic dispersion amount to compensate for dispersion of a coherently received optical signal and performs arithmetic of a signal power of the optical signal that is dispersion compensated. The computation unit performs computation of an evaluation function when a signal power and a delayed signal power obtained by applying a predetermined delay to the signal power satisfy a threshold condition. The evaluation function is a function for evaluating whether the assumed chromatic dispersion amount is a chromatic dispersion amount of the optical signal using the difference between the signal power and the delayed signal power. The chromatic dispersion amount calculation unit calculates a chromatic dispersion amount of the optical signal based on the computation result of the evaluation function by the computation unit when each of a plurality of different assumed chromatic dispersion amounts is used.

Abstract: A method and apparatus for generating a four-level pulse amplitude modulation (PAM-4) optical signal are disclosed. The method of generating a PAM-4 optical signal may include outputting a PAM-4 electrical signal, generating a PAM-4 optical signal based on the PAM-4 electrical signal, extracting feature information of the PAM-4 electrical signal from the PAM-4 electrical signal, and generating a control signal to control an operation of generating the PAM-4 electrical signal based on the feature information.

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: An interface or communications system for a neural probe, the interface or communications system comprising at least one probe interface, an optical communications interface and a processing system. The at least one probe interface is configured to interface with at least one neural probe so as to receive data collected by the probe. The processing system is configured to process the data from the at least one probe interface and provide the processed data to the optical communications interface. The optical communications interface is configured to communicate the processed data to a remote device, e.g. using optical wireless communications. The optical communications interface has the large bandwidth available that will allow the scaling up of recording sites from the neural probe without resulting in undue size, weight and/or power consumption.

Abstract: In accordance with an embodiment, a device configured to detect a presence of at least one digital pattern within a signal includes J memory circuits having respectively Nj memory locations; and processing circuitry comprising an accumulator configured to successively address the memory locations of the J memory circuits in a circular manner at frequency F and during an acquisition time, and successively accumulate and store values indicative of a signal intensity in parallel in the J addressed memory locations of the J memory circuits, and a detector configured to detect the possible presence of the at least one pattern.

Abstract: Methods and apparatus for an imaging sensor having background subtraction including integrating photocurrent on a first capacitor, and, after a voltage on the first capacitor reaches a threshold, directing the photocurrent to a second capacitor. The first capacitor can be reset. This can be repeated a given number of times until a value on the second capacitor is read out.

Abstract: Methods and systems for automated health assessment of fiber optic links of a fiber optic communication system are described. Tables are used to describe the fiber optic links, including access addresses to communication modules used in the links. Telemetry data representative of operation of the communication modules can be read via the access addresses into a central station. OTDR/OFDR measurement data of fiber optic segments used in the links can be read via the access addresses into the central station. The telemetry and/or OTDR/OFDR measurement data can be used by the central station for comparison against reference data to assess health of the links. The communication modules locally and continuously capture the telemetry data to detect transient events that may be the result of tampering of the links.

Abstract: A display device that can correct the threshold voltage of a driving transistor without a correction of image data is provided. A display device including a pixel provided with a driving transistor, a display element, and a memory circuit and a correction data generation circuit is related. One of a source and a drain of the driving transistor is electrically connected to one electrode of the display element, and a gate of the driving transistor is electrically connected to the memory circuit. In a first period, the correction data generation circuit generates correction data that is data for correcting the threshold voltage of the driving transistor. In a second period, first data is written to the memory circuit. In a third period, second data is supplied to the pixel, whereby third data in which the second data is added to the first data is generated. In a fourth period, an image corresponding to the third data is displayed by the display element.

Abstract: The present disclosure provides an optical communication drive circuit and method, an optical communication transmitter, an optical communication system, and a vehicle. The optical communication drive circuit includes a clock circuit and a modulation circuit. The clock circuit is configured to output a clock signal with an initial frequency signal as an input under control of information to be transmitted. The clock signal includes alternating first and second frequency signals, the first frequency signal and the second frequency signal having different frequencies and being generated based on the initial frequency signal; and the modulation circuit is configured to modulate an optical signal by the clock signal to obtain a modulated optical signal.

Abstract: Modulation schemes for 5G/6G are disclosed that include amplitude-variation modulation states as well as prior-art constant-amplitude states. In an amplitude-variation scheme, the amplitude of the transmitted signal is varied during each message element instead of being held constant throughout the message element. The variation may be a stepwise amplitude switch between two amplitude levels, or a linear amplitude ramp, according to the modulation scheme. The amplitude-variations provide many additional modulation states, thereby providing higher bits per message element, so that messages can be made shorter, with no decrease in message content. In addition, methods to mitigate frequency shifts, sideband generation, and signal spill-over to adjacent subcarriers are provided. With amplitude-variation modulation, the network throughput can be increased and expenses can be decreased, according to some embodiments.

Abstract: Systems and methods for longitudinal performance monitoring of an optical communication line communicably connecting a transmitting device to a receiving device for transmitting a signal therebetween. The method comprises receiving the signal at the receiving device, the signal having been affected by propagative impairments accumulated along the optical communication line, generating, at the receiving device, a linear signal based on the received signal, generating, based on the linear signal, a plurality of signal templates, and determining correlation values between the received signal and each signal template of the plurality of signal templates, each correlation value being indicative of a local longitudinal performance of the optical communication line.

Abstract: An optical transmitter and a method of producing a low-photon-density modulated optical signal are disclosed. The optical transmitter and method include an optical source configured to emit a continuous optical carrier waveform, a dilation module configured to apply a spreading code to a data payload to spread each of the plurality of symbols in time to expand the symbol duration by a dilation factor and produce a corresponding plurality of time-dilated symbols, the plurality of time-dilated symbols having a lower photon density than the plurality of symbols; a mapping module configured to map the plurality of time-dilated symbols to a modulation scheme; and a modulator configured to modulate the optical carrier waveform with the plurality of time-dilated symbols according to the modulation scheme to produce the low-photon-density modulated optical signal encoded with the plurality of time-dilated symbols corresponding to the data payload.

Abstract: A modified optical PAM communication system using multiple laser sources to generate each amplitude level. The systems can be applied separately or in conjunction with another modulation system such as SDM, MDM, WDM, TDM, or other communication systems. In an embodiment, a PAM-4 system will increase data rate by a factor of two, but more complicated schemes using more lasers can be utilized to generate higher efficiency schemes. For example, a 25 Gbps NRZ signal will give 50 Gbps PAM-4 signal and higher laser systems can generate PAM-8 or PAM-16 for 75 and 100 Gbps systems respectively. These can be further applied to SDM systems to generate higher data rates equivalent to the number of SDM channels multiplied by the PAM efficiency. In embodiments, the invention may combing PAM with WDM and SDM to achieve multiple bits per symbol.

Abstract: A modified optical PAM communication system using multiple laser sources to generate each amplitude level. The systems can be applied separately or in conjunction with another modulation system such as SDM, MDM, WDM, TDM, or other communication systems. In an embodiment, a PAM-4 system will increase data rate by a factor of two, but more complicated schemes using more lasers can be utilized to generate higher efficiency schemes. For example, a 25 Gbps NRZ signal will give 50 Gbps PAM-4 signal and higher laser systems can generate PAM-8 or PAM-16 for 75 and 100 Gbps systems respectively. These can be further applied to SDM systems to generate higher data rates equivalent to the number of SDM channels multiplied by the PAM efficiency. In embodiments, the invention may combing PAM with WDM and SDM to achieve multiple bits per symbol.

Abstract: Various embodiments of signal shaping systems are disclosed. In some embodiments, a signal shaping system comprises an input configured to receive an input signal. The input signal is transmitted as an optic signal. The signal shaping system comprises a first delay module to generate a first delay signal with a first delay compared to the input signal and a second delay module to generate a second delay signal with a second delay compared to the first delay signal. An inverter is configured to invert the first delay signal to generate an inverted first delay signal. A signal addition operation module is configured to add the inverted first delay signal and the second delay signal together and create a first pulse with a duration of the second delay and a second pulse with a duration of the second delay. An amplifier is configured to cut off the first pulse and amplify the second pulse. A bias loop module is configured to keep the amplifier near a cutoff region.

Abstract: A method of controlling an optical transmitter comprising a determining step, a dividing step and a determining step. In the determining step, a full range of an optical signal output from a light-generating device is determined by setting an upper and a lower limit thereof by keeping power of a continuous wave (CW) light constant and varying an electrical driving signal, the optical signal having 2n optical levels where n is an integer. In the dividing step, the full range of the optical signal is divided into sub-ranges each between the neighbor optical levels including the upper limit and the lower limit of the full range, the sub-ranges having preset ratios. In the determining step, electrical levels of the electrical driving signal are determined based on a non-linear transfer characteristic of the light-generating device between the electrical driving signal supplied thereto and the optical signal output therefrom.

Abstract: In a coherent optical receiver device, the dynamic range considerably decreases in the case of selectively receiving the optical multiplexed signals by means of the wavelength of the local oscillator light, therefore, a coherent optical receiver device according to an exemplary aspect of the invention includes a coherent optical receiver receiving optical multiplexed signals in a lump in which signal light is multiplexed; a variable optical attenuator; a local oscillator connected to the coherent optical receiver; and a first controller controlling the variable optical attenuator by means of a first control signal based on an output signal of the coherent optical receiver; wherein the coherent optical receiver includes a 90-degree hybrid circuit, a photoelectric converter, and an impedance conversion amplifier, and selectively detects the signal light interfering with local oscillation light output by the local oscillator out of the optical multiplexed signals; and the variable optical attenuator is disposed

Abstract: A frequency comb generating device is described. The frequency comb generating device comprises a pulsed optical light source, a sequence generator, a light receiving unit and a switching unit. The sequence generator is configured to generate a repeating sequence signal and to forward the repeating sequence signal at least to the switching unit. The pulsed optical light source is configured to generate electromagnetic wave packets and is synchronized with the sequence generator. The light receiving unit is configured to receive the electromagnetic wave packets and to convert the electromagnetic wave packets into an electrical signal. The switching unit is configured to at least one of control the pulsed optical light source, control the light receiving unit, attenuate the electromagnetic wave packets, phase shift the electromagnetic wave packets, attenuate the electrical signal, and phase shift the electrical signal based on the repeating sequence signal.

Abstract: The present invention discloses an apparatus. The apparatus includes: a coherent receiving unit, configured to perform coherent synthesis on a received to-be-detected optical signal and a multi-wavelength local oscillation laser beam, and convert a coherent receiving signal formed by means of the coherent synthesis into an analog electrical signal; a data acquiring unit, configured to acquire the analog electrical signal output by the coherent receiving unit, and convert the analog electrical signal into a digital signal; a power spectrum generation unit, configured to process the digital signal output by the data acquiring unit, to generate a continuous full power spectrum of the to-be-detected optical signal; and an optical performance parameter monitoring unit, configured to monitor, according to the continuous full power spectrum generated by the power spectrum generation unit, an optical performance parameter of a transmission link carrying the to-be-detected optical signal.

Abstract: In a coherent optical receiver device, the dynamic range considerably decreases in the case of selectively receiving the optical multiplexed signals by means of the wavelength of the local oscillator light, therefore, a coherent optical receiver device according to an exemplary aspect of the invention includes a coherent optical receiver receiving optical multiplexed signals in a lump in which signal light is multiplexed; a variable optical attenuator; a local oscillator connected to the coherent optical receiver; and a first controller controlling the variable optical attenuator by means of a first control signal based on an output signal of the coherent optical receiver; wherein the coherent optical receiver includes a 90-degree hybrid circuit, a photoelectric converter, and an impedance conversion amplifier, and selectively detects the signal light interfering with local oscillation light output by the local oscillator out of the optical multiplexed signals; and the variable optical attenuator is disposed

Abstract: An optical phantom produces a time-resolved diffuse reflectance spectrum and includes: a light source; a spatial light modulator; and an optical delay line including optical fibers of different length that produce different time-of-flight distributions, such that different time-of-flight distributions are combined and produce phantom light having the time-resolved diffuse reflectance spectrum.

Abstract: Disclosed systems, methods, and computer program products enable high symbol-rate optical Nyquist signal generation with roll-off factors approaching zero by combining digital and all-optical methods. The combined digital and all-optical methods utilize all-optical sine-shaped pulse generation and orthogonal time-division multiplexing with quadrature amplitude modulation using digital Nyquist signals. Disclosed embodiments exhibit inter-channel-interference penalties that are less than 0.5-dB for both 75-GBaud and 125-GBaud optical Nyquist signals, in contrast to conventional signals generated using rectangular waveform driving signals that exhibit penalties greater than 2.5-dB and 1.5-dB for 75-GBaud and 125-GBaud signals, respectively. The disclosed embodiments, therefore, enable significant improvement over conventional systems by reducing inter-channel-interference penalties caused by excess modulation induced bandwidth.

Abstract: A method implemented by a first network element (NE) comprises receiving, by a receiver of the first NE, a burst from a second NE, wherein the burst comprises at least one training symbol (TS), storing, by a memory of the first NE, a channel response for a link between the first NE and the second NE, wherein the first NE is communicatively coupled to the second NE, wherein the channel response is based on a current channel response estimated using at least one TS in the burst and a previously stored channel response, and wherein the previously stored channel response is based on a plurality of bursts previously received from the second NE, and compensating, by a processor coupled to the receiver and the memory of the first NE, modulated symbols in the burst using the channel response.

Abstract: A method implemented by a visible light communication (VLC) device comprises determining, by a processor of the VLC device, n time slots for a signal block based on a dimming value, the signal block specifying a predetermined duration of time and the signal block being divided equally into n time slots, with the dimming value specifying a light intensity of light to be emitted by the light source, determining, by the processor, w pulses to be transmitted during one or more of the n time slots of the signal block, based on the dimming value and according to a pulse pattern indicating a position of the w pulses transmitted during the one or more of the n time slots, and determining, by the processor, a codeword based on n and w, the codeword corresponding to the pulse pattern.

Abstract: Optical wireless communication techniques are described and claimed. In one embodiment, the disclosure relates to method and apparatus to provide optical signaling with visible light having variable pulse position modulation (VPPM). The optical signal includes a Start Frame Delimiter (SFD) which indicates beginning of an asynchronous optical signaling. The VPPM signaling includes a lower frequency time varying amplitude component that when subsampled by a low frame rate camera results in alias induced flicker or blinking. Such signals are quickly recognizable as signals with modulated data. In another embodiment, the disclosure provides a system, device and method for decoding a Start Frame Delimiter (SFD) to indicate arrival of incoming VPPM optical data.

Abstract: Systems and methods are disclosed with one or more light emitting diodes (LEDs) with at least one optical transmitter and receiver optically coupled to an optical network over 1 Mbps using at least one LED with a first mode to communicate location and a second mode to communicate using broadband optical transmission; and a controller coupled to the LEDs, the controller communicating with the optical network using the optical transmitter and receiver.

Abstract: Visualizing conditions of information technology environment includes creating a visual with an initial unit set and an interactive section, each unit in the initial unit set depicting at least two types of information about at least one current condition in the information technology environment and changing the visual in response to commands from the interactive section to reveal data about the information technology environment.

Abstract: In a coherent optical receiver device, the dynamic range considerably decreases in the case of selectively receiving the optical multiplexed signals by means of the wavelength of the local oscillator light, therefore, a coherent optical receiver device according to an exemplary aspect of the invention includes a coherent optical receiver receiving optical multiplexed signals in a lump in which signal light is multiplexed; a variable optical attenuator; a local oscillator connected to the coherent optical receiver; and a first controller controlling the variable optical attenuator by means of a first control signal based on an output signal of the coherent optical receiver; wherein the coherent optical receiver includes a 90-degree hybrid circuit, a photoelectric converter, and an impedance conversion amplifier, and selectively detects the signal light interfering with local oscillation light output by the local oscillator out of the optical multiplexed signals; and the variable optical attenuator is disposed

Abstract: Systems and methods are disclosed for use in conjunction with a standardized electrical connector of a conventional light bulb or tube with one or more light emitting diodes (LEDs) electrically coupled to at least one electrical connector compatible with a conventional light connector, wherein the LEDs include at least one multiband-type ultra-wideband (UWB) transceiver having one or more optical channels defined using one or more OFDM bands; and a controller coupled to the LEDs, the controller adjusting LED light output and communicating with the optical network using the optical transmitter and receiver. In other embodiments, the LEDs include at least one optical transmitter and receiver optically coupled to an optical network using at least one LED with a first mode to generate light and a second mode to receive optical transmissions using ambient light.

Abstract: An optical device incorporates into the same physical structure the functionality of two or more wavelength selective switches. The wavelength components associated with the first optical switch are isolated from the wavelength components associated with the second optical switch by their spatial displacement along one axis on a programmable optical phase modulator. Remaining crosstalk between the components is reduced by spatially separating the components of the two wavelength switches having the same wavelength along another axis of the programmable optical phase modulator.

Abstract: Enhancements in optical beam propagation performance can be realized through the utilization of ultra-short pulse laser (USPL) sources for laser transmit platforms, which are can be used throughout the telecommunication network infrastructure fabric. One or more of the described and illustrated features of USPL free space-optical (USPL-FSO) laser communications can be used in improving optical propagation through the atmosphere, for example by mitigating optical attenuation and scintillation effects, thereby enhancing effective system availability as well as link budget considerations, as evidenced through experimental studies and theoretical calculations between USPL and fog related atmospheric events.

Abstract: Systems and methods are disclosed for use in conjunction with a standardized electrical connector of a conventional light bulb or tube with one or more light emitting diodes (LEDs) electrically coupled to at least one electrical connector compatible with a conventional light connector, wherein the LEDs include at least one multiband-type ultra-wideband (UWB) transceiver having one or more optical channels defined using one or more OFDM bands; and a controller coupled to the LEDs, the controller adjusting LED light output and communicating with the optical network using the optical transmitter and receiver. In other embodiments, the LEDs include at least one optical transmitter and receiver optically coupled to an optical network using at least one LED with a first mode to generate light and a second mode to receive optical transmissions using ambient light.

Abstract: A light transmitter transmits multiple light packets, each formatted to include a predetermined phase synchronization field (PSF) and a same message comprising a series of bits. The PSF and each bit are each represented as light that is intensity modulated over a bit period at a corresponding frequency. The light packets are transmitted at different start-times to cause a receiver to sample each packet with a different phase of a fixed, asynchronous sample timeline. The PSF and message are demodulated from each of the sampled light packets. If the demodulated PSF matches the predetermined PSF, then the corresponding demodulated message is declared valid.

Abstract: A lighting apparatus for visible light communication includes at least one luminaire body and a visible-light-communication-signal-outputting part. The luminaire body includes a light source that includes an LED. The visible-light-communication-signal-outputting part is configured to output a modulation signal to the luminaire body. The luminaire body further includes: a power supply circuit configured to dim the light source; a switch element for modulating an output current that is supplied from the power supply circuit to the light source; a resistor connected in parallel with the switch element; and a photo-coupler configured to receive the modulation signal output from the visible-light-communication-signal-outputting part. The visible-light-communication-signal-outputting part is provided outside the luminaire body, and is configured to transmit the modulation signal via the photo-coupler.

Abstract: A high-speed signal generator. A digital signal processing (DSP) block generates a set of N (where N is an integer and N?2) parallel digital sub-band signals, each digital sub-band signal having frequency components within a spectral range between 0 Hz and ±Fs/2, where Fs is a sample rate of the digital sub-band signals. A respective Digital-to-Analog Converter (DAC) processes each digital sub-band signal to generate a corresponding analog sub-band signal, each DAC having a sample rate of Fs/2. A combiner combines the analog sub-band signals to generate an output analog signal having frequency components within a spectral range between 0 Hz and ±NFs/2.

Abstract: This invention concerns real-time multi-impairment signal performance monitoring. In particular it concerns an optical device, for instance a monolithic integrated photonics chip, comprising a waveguide having an input region to receive a signal for characterization, and a narrow band CW laser signal. A non-linear waveguide region to mix the two received signals. More than one output region, each equipped with bandpass filters that extract respective discrete frequency bands of the RF spectrum of the mixed signals. And, also comprising (slow) power detectors to output the extracted discrete frequency banded signals.

Abstract: An optical communication method includes converting an optical pulse amplitude modulation (PAM) signal to a square QAM signal using an optical delay interferometer (DI) to perform all-optical PAM to QAM conversion in the DI; performing optical de-correlation of I and Q tributaries of the QAM signal to avoid frequency dependent attenuation in RF cabling which impacts signal quality; and finding optimal phase control mechanism of the DI by monitoring and equalizing down-converted I and Q electrical signal amplitudes, using coherent detection; and emulating a square quadrature amplitude modulation (QAM) optical signal with duplicated data copies.

Abstract: Systems that allow for DFE functionality to be eliminated from the receiver side of a communication system and for a DFE-like functionality to be implemented instead at the transmitter side of the communication system are provided. By removing the DFE functionality from the receiver side, error propagation can be eliminated at the receiver and receiver complexity can be reduced drastically. At the transmitter side, the DFE-like functionality provides the same DFE benefits, and with the transmitter environment being noise-free, no errors can occur due noise boosting, for example. The DFE-like functionality at the transmitter side can be implemented using non-linear (recursive or feed-forward) pre-coders or a combination of non-linear pre-coders and linear filters, which can be configured to invert a net communication channel between the transmitter and the receiver. Embodiments particularly suitable for fiber optic channels and server backplane channels are also provided.

Abstract: Disclosed herein are a visible light communication method and apparatus. The visible light communication method includes determining whether a current location is the start of a symbol of a transmission signal, setting a sample index, a signal accumulated value for an accumulation region of a front half portion of the symbol, and a signal accumulated value for an accumulation region of a rear half portion of the symbol, determining whether the sample index belongs to an accumulation region of the front or rear half portion of the symbol, and accumulating samples of the transmission signal in accordance with the location to which the sample index belongs, determining whether a current location corresponds to the end of the symbol, and outputting a Variable Pulse Position Modulation (VPPM) communication signal corresponding to the transmission signal.

Abstract: In an optical data communication system transmitter, in which a laser is driven with a laser modulation signal in response to a serial data stream, the laser driver adds peaking to a bit other than the first bit following a bit transition.

Abstract: Disclosed herein are a visible light communication method and apparatus. The visible light communication method includes determining a dimming level variable to perform minute dimming control, selecting an upper dimming symbol and a lower dimming symbol, which belong to Variable Pulse Position Modulation (VPPM) symbols, based on the dimming level variable, determining at least one of the number of upper dimming symbols to be sent and the number of lower dimming symbols to be sent based on the dimming level variable, and generating a transmission sequence corresponding to the dimming level variable by combining the upper dimming symbols and the lower dimming symbols based on the number of symbols to be sent.

Abstract: Systems and methods are disclosed to provide an upstream rate between 1 Gbps and 10 Gbps in a cost effective manner in a 10 GEPON. In an embodiment, an optical network unit (ONU) transmitter includes a burst transceiver and a physical layer (PHY) including a high performance digital to analog converter (DAC), a pulse amplitude modulation (PAM) module configured to encode end user data using a modulation scheme having more than two levels, and a laser. The ONU transmitter transmits the encoded end user data to an optical line terminal (OLT) receiver, which demodulates the data using a PAM demodulator and sends it to a service provider.

Abstract: A technique in which an outgoing signal is encoded to have multiple signal levels to modulate a light source, in which respective signal levels are indicative of different signal states of more than one bit. The multi-level signal is transmitted on a passive optical network (PON) having passive splitters to split the modulated light to transmit the light having multiple signal levels to a plurality of destinations via the PON.

Abstract: A method of tuning the time duration of laser output pulses, the method including spectrally dispersing optical pulses and further comprising providing an optical pulse having a time duration and a spectral bandwidth; spectrally dispersing (243, 245) the optical pulse so as to provide a selected change in the time duration of the pulse responsive to the spectral bandwidth of the pulse; outputting (226) an optical output pulse having a first time duration that is responsive to the selected change in time duration; providing another optical pulse; changing the amount of spectral bandwidth of the another optical pulse (272) to be different than that of the optical pulse or changing the amount of spectral dispersion so that spectrally dispersing the another optical pulse provides a change in time duration that is different than the selected change; and outputting (226) another optical output pulse having a second time duration that is responsive to the different change in time duration, the second time duration o