Abstract: A filter circuit for use with a system configured to be coupled with an electrical load, the filter circuit comprising a first filter, wherein the first filter is configured to receive a first voltage and provide an output voltage, the output voltage being the first voltage after filtering by the first filter, and the filter circuit is configured to adjust the bandwidth of the first filter in response to a load transient.

Abstract: This application discloses example data encoding methods, data decoding methods, and communication apparatuses. One example data encoding method includes generating M encoding units and distributing the M encoding units to N transmission channels. The M encoding units are obtained by encoding L frames. The M encoding units include at least one first-type unit. A first-type unit of the at least one first-type unit includes a first identifier. The first identifier indicates a start location that is in the first-type unit and that is of a frame header of a first frame in the L frames. M, N, and L are integers greater than or equal to 1.

Abstract: A control apparatus for generating a control signal for an electro-optic modulator is described. The control apparatus includes an RF signal source being configured to generate a radio frequency (RF) signal. The control apparatus further includes an amplitude adjustment circuit being configured to adjust an amplitude of the RF signal, thereby obtaining an adjusted RF signal. The control apparatus further includes a DC signal source being configured to generate a direct current (DC) signal. The control apparatus further includes a superposition circuit being configured to superimpose the adjusted RF signal and the DC signal, thereby obtaining the control signal for the electro-optic modulator. The control apparatus further includes a control circuit, wherein the control circuit is configured to receive at least one frequency parameter associated with the electro-optic modulator. The at least one frequency parameter includes a frequency multiplication factor and/or a target modulation frequency.

Abstract: Aspects of the subject disclosure may include, for example, identifying network elements of a wavelength division multiplexing (WDM) domain of an optical waveguide communication system that includes a group of optical-add-drop multiplexor (OADM) devices. Operations are observed for the WDM domain configured to deliver communication services configured for simultaneously transporting independent signals across a network of single optical waveguides. A demand for optical waveguide communication services is determined and the WDM network is configured according to the optical fiber communication link requirement and according to the observations. The configured WDM network includes at least one OADM device of the group of OADM devices configured to provide a WDM cross-frequency network path of the configured WDM network. Other embodiments are disclosed.

Abstract: An optical transmission device configured to: receive an input of signal interruption information from a second optical transmission device that detects a signal interruption of signal light on a transmission path, and to receive an input of ASE light after the signal interruption, has a wavelength selective switch configured to drop and/or add signal light; a memory; and a processor coupled to the memory. The processor is configured to: switch, based on the input of the signal interruption information from the second optical transmission device, control of output of the wavelength selective switch from a constant level control of the output, to a constant level control of attenuation for holding an amount of the attenuation of the signal light constant; and return the constant level control of the attenuation to the constant level control of the output, after the input of the ASE light.

Abstract: An optical transceiver may include an optical transmitter and an optical receiver. The optical transmitter and receiver may each include a grid including one or more lanes spaced apart. Each lane may correspond to a predetermined optical signal, or wavelength. The optical transmitter may include one or more sets of lasers to output one or more optical signals corresponding to the grid. Each set of laser may output a set of optical signals. Each set of lasers and, therefore, each set of optical signals may have a different passband. For example, the multiplexing and/or demultiplexing architecture may have a wide passband for the first set of optical signals and a narrow passband for the second set of optical signals. The narrow passband may be determined based on the space between two wider passbands.

Abstract: An optical transmission system is an optical transmission system for transmitting a signal from an optical transmitter to an optical receiver via at least a transmission line among one or more optical nodes and the transmission line, wherein the optical transmitter includes a digital filter that compensates for, between ripple components that are micro-fluctuating components in a frequency region representing a transmission characteristic of the signal in the optical transmitter and the optical receiver and non-ripple components of the transmission characteristic, at least the ripple components of the transmission characteristic, and at least one of the optical node and the optical transmitter includes an optical filter that compensates for the non-ripple components of the transmission characteristic.

Abstract: Provided is an optical communication system comprising a polarization-diversity optical power supply capable of supplying light over a non-polarization-maintaining optical fiber to a polarization-sensitive modulation device. In an example embodiment, the polarization-diversity optical power supply operates to accommodate random polarization fluctuations within the non-polarization-maintaining optical fiber and enables an equal-power split at a passive polarization splitter preceding the polarization-sensitive modulation device.

Abstract: A system architecture is described that allows mapping of different RF-wave directions (e.g., Angles of Arrival or “AoA-s”) to different optical-carrier wavelengths. Such mapping enables the transmission of all information captured by a phased array, including spatial information of the incoming RF waves, using a single optical fiber.

Abstract: A radio access network (“RAN”) includes a transceiver for receiving a request from user equipment (“UE”) to join the RAN. The RAN also includes a processor that is configured for: responding to the UE request by sending a message directly from the RAN to the UE to offer a set of first terms for the UE to use a cellular network of the RAN; receiving a response from the UE agreeing to the set of first terms; and in response to the UE agreeing to the set of first terms, connecting the UE to use a cellular network of the RAN.

Abstract: A 10 G rate OLT terminal transceiver integrated chip based on XGPON and DFB laser includes: a burst mode receiver RX, a continuous mode transmitter TX and a digital control unit DIGIITAL. The burst mode receiver RX amplifies an optical signal from each ONU client into an electrical signal through a burst TIA, processes double-detection for amplitude and frequency of the electrical signal, outputs the signal whose amplitude and waveform pulse width meet the threshold requirements to the host, and uses a fast recovery module to control the timing to meet the XGPON protocol. The continuous mode transmitter TX receives the electrical signal attenuated by the PCB, and selects the bypass BYPASS path or the clock data recovery CDR path according to the degree of attenuation. The digital control unit DIGIITAL is used to provide control signals for the burst mode receiver RX and the continuous mode transmitter TX.

Abstract: Systems and methods for automatic link calibration include subsequent to installation of equipment for the amplified optical section, obtaining power measurements of optical spectrum in the optical section; obtaining properties of fiber in the amplified optical link; analyzing the power measurements and the properties of the fiber to determine settings for the equipment for calibration thereof; and automatically configuring the settings for the equipment. The settings are based on the power measurements and the properties of the fiber to achieve a target launch power per span in the amplified optical section, and wherein the target launch power is based on Optical Signal-to-Noise Ratio (OSNR) and non-linearity in the amplified optical section.

Abstract: An apparatus includes an optical wavelength multiplexer to multiplex a sequence of optical wavelength channels. The optical wavelength multiplexer comprises a first passive optical filter to combine odd channels of the sequence of optical wavelength channels into a first multiplexed optical signal, a second passive optical filter to combine even channels of the sequence of optical wavelength channels into a second multiplexed optical signal, and an optical combiner to combine the odd channels and the even channels into a composite optical signal. The optical wavelength multiplexer comprises variable optical attenuators, and an electronic controller to operate the variable optical attenuators to substantially block one or more adjacent optical wavelength channels adjacent to a particular optical wavelength channel provisioned to the optical wavelength multiplexer in response to a width for the particular optical wavelength channel being larger than a width of the adjacent optical wavelength channel(s).

Abstract: A system and method for wavelength detection includes one or more detection stages configured for receiving at least a portion of an optical carrier. Each stage includes a splitter for splitting the signal into two arms. A 90-degree optical hybrid and in-phase (I-channel)/quadrature (Q-channel) differential detectors generate I-channel and Q-channel differential signals based on the hybrid outputs. A gas cell or like multi-point wavelength reference path also receives the input signal and provides a set of reference absorption wavelengths converted into the electrical domain by a reference photodetector. A logic device receives sets of detection signals (including I-channel and Q-channel differential signals and the set of reference wavelengths, all corresponding to a common measurement time) and determines a wavelength of the optical carrier based on an arctangent of a ratio of the Q-channel and I-channel differential signals, mapped to the set of reference absorption wavelengths.

Abstract: Systems and methods are provided for generating a model for detection of seismic events. In this regard, one or more processors may receive from one or more stations located along an underwater optical route, one or more time series of polarization states of a detected light signal during a time period. The one or more processors may transform the one or more time series of polarization states into one or more spectrums in a frequency domain. Seismic activity data for the time period may be received by the one or more processors, where the seismic activity data include one or more seismic events detected in a region at least partially overlapping the underwater optical route. The one or more processors then generate a model for detecting seismic events based on the one or more spectrums and the seismic activity data.

Abstract: Embodiments of the present disclosure provide an activation method, an activation device, a control device, a network device and an optical network system. A new-system ONU is activated on a first OLT in an existing system, and then activation information of the new-system ONU is sent to a second OLT in a new system by the first OLT or by an activation agent ONU which has been activated on the second OLT, thereby enabling activation of the new-system ONU on the second OLT.

Abstract: An optical channel monitor is formed to include the capability to sense real-time changes in optical power across signal bands (optical power changes including, for example, a complete drop out of the signal band) and quickly measure the resulting spectrum, thus enabling the host to initiate advanced power balancing solutions that mitigate the extent of the power change until a permanent fix is provided. A set of signal band sensors is included with a conventional OCM, where each sensor includes a photodetector that is able to detect changes in operation along its associated incoming signal band. Control electronics are used to monitor the states of the photodetectors, with the ability to invoke an OCM scan of the complete wavelength range when a power change condition is flagged.

Abstract: Disclosed are apparatus and methods for optical coupling.

Abstract: Systems and methods are provided for planning a future network topology with associated configuration settings of existing nodes in a network and enacting changes to the configuration settings after the network has been physically changed to the planned future topology. The method can include, in response to receiving a topology plan to change a network from an initial network topology to a future network topology, determine a configuration plan to change configuration settings of one or more existing Network Elements (NEs) deployed in the network in order to transition the network from the initial network topology to the future network topology, and, in response to discovering that the network has been physically changed to match the future network topology, automatically enact the configuration plan to change the configuration settings of the one or more existing NEs.

Abstract: An optical transceiver is provided for a network communication system utilizing a coherent passive optical network (CPON). The optical transceiver includes a downstream transmitter in operable communication with an optical communication medium. The downstream transmitter is configured to schedule upstream resource allocation blocks to first and second downstream transceivers disposed along the optical communication medium at different respective locations remote from the optical transceiver. The optical transceiver further includes an upstream burst receiver system configured to simultaneously detect (i) a first upstream burst transmission sent from the first downstream transceiver along a first frequency subchannel of an optical spectrum of the CPON, and (ii) a second upstream burst transmission sent from the second downstream transceiver along a second frequency subchannel of the optical spectrum different from the first frequency subchannel.

Abstract: Provided are a link establishment method and apparatus and a computer-readable storage medium. The link establishment method includes: exchanging optical link auto-negotiation information with a terminal device through an optical link auto-negotiation channel; and in a case where exchanging the optical link auto-negotiation information is finished, establishing at least one of a traffic data channel or an optical link auto-negotiation channel; where the optical link auto-negotiation channel is independent of the traffic data channel or the optical link auto-negotiation channel; and the optical link auto-negotiation information includes at least one of information about an operating wavelength channel of the terminal device, an enabled or disabled state of forward error correction with the terminal device, a forward error correction type with the terminal device, or an operating mode of the auxiliary management channel.

Abstract: A wavelength tunable laser formed on a substrate made of single-crystal silicon is provided. The wavelength tunable laser includes a light emitting portion made of a III-V compound semiconductor, and external resonators provided with an optical filter. Cores included in the external resonators are made of one of SiN, SiON, and SiOn (n is smaller than 2).

Abstract: A method includes, for each optical fiber path in an optical network, allocating an optical wavelength channel in an optical spectrum such that the allocated optical wavelength channel is assigned to support optical communications over the optical fiber path. The method also includes updating an allocation table in response to performing the allocating for one or more of the optical fiber paths; the allocating including determining the optical wavelength channel to be allocated based on a state of the allocation table. The allocation table indicates optical wavelength channels allocated over optical fiber spans of the optical network. The method also includes defining a set of optical sub-bands to cover a part of the optical spectrum in response to a state of the allocation table satisfying a fullness property. The optical sub-bands are such that each of the allocated wavelength channels is in one of the optical sub-bands.

Abstract: An optical coupling system for coupling a light source to a photonic integrated circuit (PIC) comprises a multimode coupler configured to receive an input optical signal of a first mode. The multimode coupler triggers one or more higher-order modes from the input optical signal of the first mode. The optical coupling system also includes a mode de-multiplexer and an optical combiner. The mode de-multiplexer transfers the input optical signal of the first mode and one or more optical signals of the triggered one or more higher-order modes to respective output optical signals of the first mode. The optical combiner combines the respective output optical signals to produce a single output signal of the first mode.

Abstract: A method includes determining an operating frequency of an antenna at a component of the antenna. The method includes determining, at the component of the antenna, a filter node of a plurality of filter nodes to activate to tune the antenna to the operating frequency. The method includes transmitting power to the filter node, wherein the power is transmitted via a first optical fiber. The method also includes sending a signal from the component to a light source. The activation of the light source sends an optical signal to the filter node. The filter node adjusts a characteristic of a radiating element coupled to the filter node using the power responsive to the optical signal. Adjustment of the characteristic facilitates tuning the antenna to the operating frequency.

Abstract: Embodiments of this application disclose a data processing method, an optical transmission device, and a digital processing chip, for improving service transmission performance. In the data processing method, an optical transmission device compresses a to-be-transmitted data stream to obtain a compressed data stream. The optical transmission device then obtains a size of a first payload area corresponding to the compressed data stream and maps the compressed data stream to a data frame, where the data frame includes an overhead area and a payload area. The payload area includes the first payload area and a second payload area. The second payload area carries the compressed data stream, and the first payload area carries a forward error correction (FEC) code. The data frame is then transmitted by the optical transmission device.

Abstract: A microcontroller includes a setting unit, an encoder, a modulation circuit, and a digital-to-analog converter. The setting unit outputs a control signal. The encoder outputs a digital signal that is encoded. The modulation circuit loads at least one carrier signal on the digital signal at the logic high level and/or the logic low level according to the control signal to generate a modulated digital signal. The digital-to-analog converter converts the modulated digital signal into an analog signal, and outputs the analog signal for transmission.

Abstract: A method, system, and ASIC chip for comparing a bit error rate (BER) to a forward error correction (FEC) threshold to determine a Q margin for a codeblock; wherein the BER corresponds to the number of errors in a given amount of data; where a codeblock of a FEC corresponds to the given amount of data; wherein the FEC threshold corresponds to the maximum amount of errors per codeblock that the FEC is able to remove per given amount of data; wherein the Q margin corresponds to a difference between the BER and the FEC threshold.

Abstract: The invention provides a method for load-balanced traffic grooming in an IP over Quasi-CWDM network, including the steps of: inputting a network topology, a set of service traffics between nodes in node pairs and a null route, and when selecting one of the node pairs from the set of service traffics and establishing a traffic request between the nodes in the node pair, deleting the virtual link for which the corresponding light path has no sufficient remnant capacity in an IP layer of the network; finding the virtual link route having the lowest hop count in the IP layer, and determining whether each virtual link on the route can satisfy the service request by means of traffic grooming; and if yes, adopting the traffic grooming strategy to satisfy the service request; and if not, adopting the wave plane based strategy to establish a light path to satisfy the service request.

Abstract: Various embodiments of the disclosed PON system enable approximate leveling of the optical-modulation amplitudes in a sequence of optical bursts received by a system's OLT from a plurality of ONUs. Some embodiments additionally enable approximate leveling of the average optical power, received at the OLT from different ONUs, in such a sequence. Some embodiments may rely on control messaging between the OLT and ONUs to perform one or both types of leveling. The disclosed leveling may advantageously provide an effective tool for optimizing upstream transmission for high-speed TDM-PONs.

Abstract: A cryogenic optoelectronic data link, comprising a sending module operating at a cryogenic temperature less than 100 K. An ultrasensitive electro-optic modulator, sensitive to input voltages of less than 10 mV, may include at least one optically active layer of graphene, which may be part of a microscale resonator, which in turn may be integrated with an optical waveguide or an optical fiber. The optoelectronic data link enables optical output of weak electrical signals from superconducting or other cryogenic electronic devices in either digital or analog form. The modulator may be integrated on the same chip as the cryogenic electrical devices. A plurality of cryogenic electrical devices may generate a plurality of electrical signals, each coupled to its own modulator. The plurality of modulators may be resonant at different frequencies, and coupled to a common optical output line to transmit a combined wavelength-division-multiplexed (WDM) optical signal.

Abstract: A silicon photonics optical transceiver device includes a silicon photonics optical module and a heat conducting housing that accommodates the silicon photonic optical module therein. The heat conducting housing has an inner surface formed with a first heat dissipation portion that wraps around and is in contact with transmitter optical sub-assemblies of the silicon photonics optical module to realize thermal conduction, and a second heat dissipation portion that is in contact with a digital signal processor of the silicon photonics optical module to realize thermal conduction.

Abstract: Devices, systems and methods for encoding information using optical components are described. An example photonic filtered sampler includes a spectral shaper configured to receive an optical pulse train, a dispersive element positioned to receive an output of the spectral shaper and to expand spectral contents thereof in time, and a modulator configured to receive an output of the dispersive element and a radio frequency (RF) signal, and to produce a modulated output optical signal in accordance with the RF signal. In this configuration, one or more characteristics of the modulated output optical signal is determined based on a spectral shape provided by the spectral shaper and dispersive properties of the dispersive element.

Abstract: In some embodiments, an optical fiber transmission link, includes a length of dispersion compensating fiber (DCF), the dispersion compensating fiber coupled to a length of single-mode fiber (SMF) having a zero dispersion wavelength of 1300 nm to 1324 nm; wherein the optical fiber transmission link comprising the dispersion compensating fiber coupled to the single-mode fiber and operating at wavelengths between 1265 nm and 1375 nm increases maximum link lengths of the optical fiber transmission link by more than 60% as compared to the link length of the optical fiber transmission link with the single-mode fiber only; and wherein the maximum link length is calculated from the maximum allowed positive and negative accumulated dispersion at wavelengths between 1265 nm and 1375 nm.

Abstract: A redundant wavelength division multiplexing (WDM) device including a first common port which includes a collimator configured to transmit a first optical beam. The first beam includes a first plurality of optical signals. A second common port includes a collimator configured to transmit a second optical beam that includes a second plurality of optical signals. The second common port is spaced apart from the first common port and a plurality of filters define an optical path for each of the first optical beam and the second optical beam. Each filter is oriented to interact with each of the first optical beam and the second optical beam. A method of processing light includes transmitting one of the first optical signals of a first wavelength through a first filter and transmitting one of the second optical signals of the first wavelength through the first filter.

Abstract: Systems and methods include causing perturbations across optical spectrum; probing responses across some or all of the optical spectrum after the perturbations; and determining a nonlinear transfer function based on the responses. The nonlinear transfer function can include a representation of any of end-to-end channel powers, Signal-to-Noise Ratio (SNR), Noise-to-Signal Ratio (NSR), Bit Error Rate (BER), Q, and Mean Squared Error (MSE).

Abstract: A method for steering a beam is disclosed. According to the method, a scene is scanned with a surface emitting grating optically coupled to a free propagation region. The free propagation region is optically coupled to waveguides. The waveguides are disposed at different angles to the surface emitting grating. The scanning includes scanning in a first dimension by cycling through a cross connect to illuminate each waveguide of the waveguides. Scanning in a second dimension is performed by tuning a wavelength of light used to illuminate the waveguides.

Abstract: An optical transceiver includes an input assembly, an output port, a fiber patch panel, multiple first optical fibers and multiple second optical fibers. The input assembly is arranged on a circuit board and has a first input port and a second input port. The fiber patch panel is arranged between the input assembly and the output port, and has multiple first fiber patch slots and multiple second fiber patch slots. The first optical fibers are connected to the first input port and the output port. The first optical fiber passes through the first fiber patch slot and the second fiber patch slot. The second optical fibers are connected to the second input port and the output port. The second optical fiber passes through the first fiber patch slot and the second fiber patch slot. The second fiber patch slot accommodates the first optical fiber and the second optical fiber.

Abstract: A communication device includes: a MAC unit that processes a main signal including a payload, and determines a communication timing of the main signal; a communication unit that performs, based on the communication timing, at least one of transmission processing for E/O converting the main signal acquired from the MAC unit, and transmitting the main signal to a communication counterpart device, and reception processing for O/E converting the main signal received from the communication counterpart device; a main signal transmission line through which the main signal is transmitted between the MAC unit and the communication unit; and a control information transmission line that is provided separately from the main signal transmission line, and through which communication timing data that is data indicating the communication timing is transmitted from the MAC unit to the communication unit.

Abstract: A communication system may an optical signal generator and a signal path. The generator may generate one or more optical local oscillator (LO) signals and an optical frequency comb. Optical paths and an optical demultiplexer may distribute the optical LO signal(s) and the frequency comb to photodiodes in one or more access points. The photodiodes may be coupled to antenna radiating elements. The optical paths may illuminate each photodiode using a signal pair that includes one of the optical LO signals and one of the carriers from the frequency comb. The photodiodes may convey wireless signals using the antenna radiating elements at frequencies given by the differences in frequency between the signals in the signal pairs. The radiating elements may concurrently convey the wireless signals with different external devices at different frequencies, with different devices at the same frequency, and/or with the same device at the same frequency.

Abstract: An optical modulator comprises, as optical modulator components, first and second transmitter chains and a first optical time division multiplex, OTDM, generator arranged to receive time interleaved optical pulses generated by one of said optical modulator components.

Abstract: Consistent with the present disclosure, a local oscillator is provided in a receiver. The local oscillator laser a first and second mirrors and phase section and heaters are provided adjacent each portion of the laser, such that the temperature and thus the frequency of light output from the local oscillator laser may be tuned. Applying electrical power, such as a current or voltage to the phase section may result in rapid frequency tuning of light output from the local oscillator laser but over a limited frequency range. Temperature changes to the mirror sections, however, may afford frequency tuning over a wider range, but frequency tuning the mirror sections requires more time than that required to tune the phase section. Consistent with the present disclosure, a tuning method and apparatus is provided that optimizes laser tuning by selectively tuning the phase and mirror sections.

Abstract: A wavelength division multiplexing device includes an alignment substrate configured to provide alignment between optical components of the device. The device includes a plurality of collimating lenses, and the alignment substrate includes a plurality of aligners. Each of the aligners is configured to place a respective one of collimating lenses in a predetermined position and a predetermined orientation with respect to the other collimating lenses. The alignment substrate thereby provides passive alignment of the collimating lenses with a designed optical path. The substrate may also include visual alignment markings that provide an indication of the placement of multi-layer thin film filters so that the filters define an actual optical path in alignment with the designed optical path, and integrated optical waveguides that provide an optical beam to each of the collimating lenses.

Abstract: Consistent with the present disclosure, a photonic integrated circuit (PIC) is provided that has 2 N channels (N being an integer). The PIC is optically coupled to N optical fibers, such that each of N polarization multiplexed optical signals are transmitted over a respective one of the N optical fibers. In another example, each of the N optical fibers supply a respective one of N polarization multiplexed optical signals to the PIC for coherent detection and processing. A multiplexer and demultiplexer may be omitted from the PIC, such that the optical signals are not combined on the PIC. As a result, the transmitted and received optical signals incur less loss and amplified spontaneous emission (ASE) noise. In addition, optical taps may be more readily employed on the PIC to measure outputs of the lasers, such as widely tunable lasers (WTLs), without crossing waveguides.

Abstract: The present disclosure discloses a time service and positioning network system for an underground chain-shaped large space in a coal mine. The system adopts a base station-level network internal time synchronization method which takes an optical fiber time service as a main part and takes a satellite time service as an auxiliary part to construct a time service and positioning network system with an unified time within the ad-hoc network base stations, based on the ad-hoc network base stations linearly arranged in the underground chain-shaped large space in the coal mine. Through the network construction, the network stabilization and the network application, the system unifies the time reference of the base station-level network and improves the positioning accuracy of the network application by utilization of the base station-level network internal time synchronization method.

Abstract: Optical interconnect topologies may be provided using microLEDs. The topologies may interconnect ICs. The optical interconnect topologies may be used in some instances in place of electrical busses.

Abstract: An optical transmission system includes a transmitting node that transmits wavelength light of an operational path to an optical waveguide, and a receiving node that receives the wavelength light from the optical waveguide. The transmitting node includes a light source that generates spontaneously emitted light and a wavelength selector that generates and outputs dummy wavelength light from the spontaneously emitted light generated by the light source. The receiving node includes an extractor that extracts spectral data of the dummy wavelength light passed in the optical waveguide. The optical transmission system further includes an obtainer that obtains a band state of the operational path from the spectral data of the dummy wavelength light extracted by the extractor.

Abstract: Plural grating couplers having grating conditions different from each other and plural optical waveguides respectively connected with the plural grating couplers are included. The plural grating couplers have the same arraying directions of gratings. Further, each of the plural grating couplers has a different grating interval as a grating condition. Further, plural reflection units respectively provided to the plural optical waveguides are included.

Abstract: An optical communication system according to the present invention cancels waveform distortion due to wavelength dispersion by extracting the spectrum of a transmitted optical signal and passing the optical signal to a fiber having a dispersion value opposite to a dispersion amount corresponding to a transmission distance received by the spectrum component and compensates for a transmission path loss due to the fiber having the opposite dispersion value using optical splitters having different split ratios. With this configuration, the present invention can compensate for waveform distortion due to wavelength dispersion by a simple method in an access network and achieve an increase in the reachable transmission distance of the farthest user or an increase in the number of connectable users.

Abstract: Optical network systems and components are disclosed, including a transmitter comprising a digital signal processor that receives data; circuitry that generate a plurality of electrical signals based on the data; a plurality of filters, each of which receiving a corresponding one of the plurality of electrical signals, a plurality of roll-off factors being associated with a respective one of the plurality of filters; a plurality of DACs that receive outputs from the digital signal processor, the outputs being indicative of outputs from the plurality of filters; a laser that supplies light; and a modulator that receives the light and outputs from the DACs, and supplies a plurality of optical subcarriers based on the outputs, such that one of the optical subcarriers has a frequency bandwidth that is wider than remaining ones of the optical subcarriers, said one of the optical subcarriers carrying information for clock recovery.