Abstract: An optical repeater device includes an amplifier module and a monitoring control circuit. The optical amplifier module includes an amplifier optical circuit including a plurality of amplification cores that amplify signal light propagating through different cores, and an optical amplifier control circuit that receives detection results from optical detectors at a plurality of signal light waveguide points of the amplifier optical circuit and generates a control signal directed to an excitation light source.

Abstract: An excitation light source apparatus capable of assuring an excellent optical transmission characteristic even at occurrence of a gain tilt is provided. The excitation light source apparatus comprises an excitation light outputting means, a control signal detection means, a control signal detection means, an excitation light control means, and a multiplexing means. The excitation light outputting means outputs excitation light for Raman amplification. The control signal detection means detects a control signal of the excitation light outputting means from beams of WDM signal light transmitted through optical fibers in an upstream direction and a downstream direction. The excitation light control means controls the excitation light outputting means, based on the control signal. The multiplexing means multiplexes the excitation light and each of the beams of the WDM signal light, and outputs the respective multiplexed beams of light to the optical fiber.

Abstract: Various embodiments for a system and method for a range-enhanced high-speed free-space optical communication are described herein. Generally, the optical communication system may include a first modulator, a second modulator and an average-power limited optical amplifier. The first modulator may receive an input optical signal and generate a modulated optical signal. The second modulator may receive the modulated signal and may be operable to turn-off a select number of pulses in each modulated pulse frame of the modulated signal to generate a low-duty cycle modulated signal. The average-power limited optical amplifier may then generate an amplified modulated signal from the low-duty cycle signal, wherein the amplified modulated signal comprises a plurality of amplified pulse frames with each amplified pulse frame defining an amplified version of a corresponding each low-duty cycle pulse frame.

Abstract: In order to improve reception sensitivity of a response signal at a terminal station, an optical transmission device includes a reception unit that receives a control signal including a predetermined instruction and a main signal, via an optical transmission path connected to the terminal station, a control unit that performs the predetermined instruction of the received control signal, an extraction unit that extracts light in a band of the control signal, a response signal generation unit that modulates the extracted light in the band of the control signal, and outputs a response signal, and a multiplexing unit that multiplexes and outputs the response signal and the main signal. The control unit controls modulation by the response signal generation unit according to the control signal.

Abstract: One embodiment provides a system for measuring optical fiber channel loss in photonic communication. During operation, a first multiplexing device receives a first signal which is a photonic signal and a second signal which is a reference light signal transmitted by a first measuring device. In response, the first multiplexing device couples the first signal with the second signal, and transmits the coupled signal via an optical fiber channel to a second multiplexing device. The second multiplexing device separates the coupled signal into a separated first signal and a separated second signal, and transmits the separated second signal to a second measuring device. The system obtains indices related to a degree of loss of the optical fiber channel based on the separated second signal.

Abstract: An optical signal monitor, including: a storage that holds a threshold value set for each of determination areas having a bandwidth set in accordance with an average grid of dummy light; a measurement section that sequentially measures an optical intensity of an inputted wavelength-multiplexed optical signal with respect to each of measurement areas obtained by dividing the determination area into areas with a bandwidth sufficiently smaller than a grid width of a monitoring-target optical signal composing the wavelength-multiplexed optical signal, and output measured values; and a section that determines that dummy light corresponding to the determination area needs introducing if each of measured values in the determination area is smaller than a threshold value, and, determines that dummy light corresponding to the determination area does not need introducing if at least one of the measured values in the determination area is equal to or larger than the threshold value.

Abstract: An optical transmission device includes: a wavelength allocation detector configured to detect wavelength allocation that indicates allocation of optical signals multiplexed in a WDM optical signal; a power adjusting unit configured to adjust powers of the optical signals multiplexed in the WDM optical signal; an optical amplifier configured to amplify the WDM optical signal output from the power adjusting unit; a power controller configured to generate a power control signal to control the power adjusting unit such that the WDM optical signal has a specified wavelength characteristic; and a correction value generator configured to generate a correction value to correct the power control signal based on the wavelength allocation. The power controller corrects the power control signal with the correction value. The power adjusting unit adjusts powers of the optical signals multiplexed in the WDM optical signal according to the corrected power control signal.

Abstract: A transmission characteristics monitoring device monitors transmission characteristics of an optical transmission path between nodes. The device detects an average power of the frequency modulated optical signal and a slope of the transmission characteristics; generates a slope function that represents a slope of the transmission characteristics between first and second frequencies; generates a corrected power value by adding an integral of the slope function to a first power measurement value detected at the first frequency; calculates the transmission characteristics at the second frequency based on a second power measurement value detected at the second frequency when the difference between the second power measurement value and the corrected power value is smaller than a specified threshold; and calculates the transmission characteristics at the second frequency based on the corrected power value when the difference is greater than the specified threshold.

Abstract: An optical device comprising, an optical input and output device comprising a first input port, a second input port, a first output port and a second output port, and an optical filtering device comprising an input port coupled to the first output port and an output port coupled to the second input port, and an optical amplifying device comprising an input port coupled to the second output port. The optical input and output device is adapted to couple the output port comprised in the optical filtering device to the input port comprised in the optical amplifying device. The optical filtering device comprises a multiple of cascaded phase shifted Bragg gratings, each being adapted to filter an associated respective optical carrier within to produce a respective output signal to the optical amplifying device.

Abstract: An optical end monitoring apparatus in an optical communication network includes an optical transmitting unit, an optical receiving unit, and a decision unit. The optical transmitting unit generates first and second optical signals with different wavelengths and transmits the first and second optical signals to the optical end terminal over an optical cable. The optical receiving unit receives reflection signals corresponding to the respective first and second optical signals. The decision unit determines whether the optical end terminal is connected to the optical cable using a difference between magnitudes of the respective received reflection signals.

Abstract: A burst-mode phase shift keying (PSK) communications apparatus according to an embodiment of the present invention enables practical, power-efficient, multi-rate communications between an optical transmitter and receiver. Embodiments may operate on differential PSK (DPSK) signals. An embodiment of the apparatus includes an average power limited optical transmitter that transmits at a selectable data rate with data transmitted in bursts, the data rate being a function of a burst-on duty cycle. DPSK symbols are transmitted in bursts, and the data rate may be varied by changing the ratio of the burst-on time to the burst-off time. This approach offers a number of advantages over conventional DPSK implementations, including near-optimum photon efficiency over a wide range of data rates, simplified multi-rate transceiver implementation, and relaxed transmit laser line-width requirements at low data rates.

Abstract: An optical transmitter includes an amplifying unit, a monitor, an identifying unit, and a controlling unit. The amplifying unit amplifies an optical signal in which an optical packet signal is mixed in optical path signals. The monitor monitors power of the optical signal on an input stage and an output stage of the optical amplifying unit, respectively. The identifying unit identifies an optical packet signal section on the input stage side based on the monitoring result on the input stage side, and identifies an optical packet signal section on the output stage side based on the monitoring result on the output stage side. The controlling unit compares the power of the identified section on the input stage side with the power of the identified section on the output stage side, and controls an amplification factor of the amplifying unit based on a power difference resulting from the comparison.

Abstract: There is provided a method and corresponding lighting device (100), and a receiver, which employs code modulation which provides a compatibility of code modulation in a dimmable lighting system. The lighting device comprises means for dimming the output light (102), which employs multiple dimming modes, each representing dimming the light output from lighting device by means of a respective dimming method, and means for embedding a code in the light output (103). The means for embedding a code in the light output employs code modulation which is based on controlling the instantaneous dimmed light output from the lighting device such that the integrated value of the dimmed light output during a time period T is modulated to embed the code. The code may then subsequently be extracted from the modulated light by means of an integrate-and-dump process at a receiver, without knowledge of the dimming method and/or dimming level of the lighting device.

Abstract: Methods, apparatus, and systems for preventing false packet acceptance in high-speed links. Under one aspect, correctable symbol errors are detected, and determination is made to whether a symbol error rate or ratio (SER) exceeds an SER threshold. In response to detection of such a condition, the link is disconnected or temporarily paused. The value for the SER threshold is determined using a statistical analysis of various link parameters to meet desired performance levels, such as a mean time to false packet acceptance (MTTFPA) of >approximately 15 billion years while providing a mean time to disconnect of >100 years.

Abstract: A portable apparatus for measuring parameters of optical signals propagating concurrently in opposite directions in an optical transmission path between two elements, at least one of the elements being operative to transmit a first optical signal (S1) only if it continues to receive a second optical signal (S2) from the other of said elements, comprises first and second connector means for connecting the apparatus into the optical transmission path in series therewith, and propagating and measuring means connected between the first and second connector means for propagating at least the second optical signal (S2) towards the one of the elements, and measuring the parameters of the concurrently propagating optical signals (S1, S2). The measurement results may be displayed by a suitable display unit. Where one element transmits signals at two different wavelengths, the apparatus may separate parts of the corresponding optical signal portion according to wavelength and process them separately.

Abstract: A burst-mode phase shift keying (PSK) communications system according to an embodiment of the present invention enables practical, power-efficient, multi-rate communications between an optical transmitter and receiver. Embodiments may operate on differential PSK (DPSK) signals. An embodiment of the system utilizes a single interferometer in the receiver with a relative path delay that is matched to the DPSK symbol rate of the link. DPSK symbols are transmitted in bursts, and the data rate may be varied by changing the ratio of the burst-on time to the burst-off time. This approach offers a number of advantages over conventional DPSK implementations, including near-optimum photon efficiency over a wide range of data rates, simplified multi-rate transceiver implementation, and relaxed transmit laser line-width requirements at low data rates.

Abstract: Embodiments of the disclosure are directed to optical dark section conditioning. An embodiment generates at least one of a broadband noise or signal at the head end of a section for a first module of the section; and operates all other modules of the section in gain control mode.

Abstract: An optical transmission system includes optical transmission apparatuses configured to transmit wavelength-division multiplexed light signals via lightpaths, each of a pair of optical transmission apparatuses includes a conditioning unit configured to adjust the optical intensities of channels included in the wavelength-division multiplexed light signal, and one or more first processors configured to control, based on a conditioning level notified, the conditioning unit; and a managing apparatus configured to manage the pair of the optical transmission apparatuses, the managing apparatus including one or more second processors configured to compute a conditioning level on a basis of system information for respective the pair of optical transmission apparatuses in the optical transmission system.

Abstract: An optical fiber data communications network in which an electro-optical transceiver couples a plurality of serial electrical data buses over a single bidirectional optical fiber link, and includes a controller that functions by oversampling the digital electrical signal on each of such buses, multiplexes them, and converts the signal into a high speed optical signal for transmission over an optical fiber.

Abstract: A repeater includes a reception part configured to receive an optical signal transmitted by wavelength division multiplexing from a preceding repeater in a path from a source to a destination; a determination part configured to determine the channel allocation of the signal received by the reception part by determining a bit rate and a modulation technique with respect to each of channels in the received signal; and a detection part configured to detect a prohibited channel not to be included in the optical signal to be transmitted from the repeater, based on the channel allocation and a predetermined criterion.

Abstract: A computer system and method for transmitting LAN signals over transport systems. LAN signals are generated in any client LAN compliant interface. A transceiver receives the client LAN signal in the LAN format. The client LAN signals are not converted to a SONET transmission format at any time before reaching the transceiver. The transceiver then converts the client LAN signal to an internal electrical LAN signal before re-clocking the internal electrical LAN signal. The re-clocked internal electrical LAN signal is then re-modulated into a second LAN signal. The second LAN signal is then transmitted to a transport system.

Abstract: An optical-branching unit enables suppression of deterioration of the transmission characteristic of a survivor signal without executing complex control of constant-power output. Optical-amplification means amplifies and supplies a input optical signal, and when not receiving the optical signal, amplifies and supplies amplified spontaneous emission that the optical-amplification means generates. Detection means detects whether the optical signal is input to the optical-amplification means. When the optical signal is not input to the optical-amplification means, control means sets gain that determines the magnitude of amplification in the optical-amplification means to a predetermined value greater than gain at the time the optical signal is input to the optical-amplification means.

Abstract: An optical transmission system includes a first node and a second node, the first node includes a first optical amplifier which outputs a signal to the second node through a first transmission line and a first monitoring unit, the second node includes a monitor which monitors a signal from the first transmission line, a second optical amplifier which outputs a signal to the first node through a second transmission line and a second monitoring unit, upon detecting disconnection from the first transmission line, the second monitoring unit transmits a notification for making power of the first optical amplifier reduced, upon receipt of the notification, the first monitoring unit reduces power of the first optical amplifier, and transmits a completion notification to the second monitoring unit, and upon not receiving the completion notification even after expiration of an allowed time, the second monitoring unit reduces power of the second optical amplifier.

Abstract: An optical transmission device according to the present invention comprises: a Raman amplification means; a main signal light sending means which sends first main signal light; a communication interruption detection light monitoring means which sends a first signal if it cannot detect communication interruption detection light; a main signal light monitoring means which sends a second signal if it cannot detect second main signal light; a light monitoring signal analysis means which sends a result of its analysis of a light monitoring signal as a third signal in a predetermined period of time; and a control means which makes the Raman amplification means suspend the generation of the excitation light, if it cannot receive the third signal even after the elapse of the predetermined period of time in the state it has received the first signal and has not received the second signal, and stops sending of the first main signal light from the main signal light sending means when receiving the second signal further.

Abstract: Changes in a signal are detected. The signal is repeatedly sampled in a synchronous manner during a predetermined interval to generate a captured eye diagram. At least one of a positive differential eye diagram or a negative differential eye diagram is generated from the captured eye diagram and a baseline eye diagram. The at least one positive or negative differential eye diagram is analyzed to determine whether a change in signal conditions is present.

Abstract: The present invention provides a long reach optical amplification device, a passive optical network and an optical signal transmission method in the communication field.

Abstract: A method and apparatus for suppressing pump-mode optical beat interference noise in a Raman amplified fiber link of an optical network, wherein a wavelength of a laser beam generated by a first pump laser and a wavelength of a laser beam generated by a second pump laser of a pair of polarization multiplexed pump lasers are detuned with respect to each other to suppress the optical beat interference, OBI, noise in the Raman amplified fiber link of said optical network.

Abstract: In accordance with the present disclosure, disadvantages and problems associated with transmitting high capacity (e.g., 400 G) optical signals may be reduced. In accordance with an embodiment of the present disclosure a method for regenerating an optical signal comprises receiving an optical signal at a network element and measuring a performance characteristic of the optical signal. The method further comprises determining that the optical signal needs regeneration based on the performance characteristic of the optical signal. The method additionally comprises performing signal regeneration of the optical signal based on the determination that the optical signal needs regeneration.

Abstract: To provide a technology of preventing an optical signal from being mistakenly recognized as an optical noise even when a surge occurs. A control device of a node that transfers signal light monitors inputted light, determines, when power of the inputted light reaches a saturation level of a monitor unit as a result of monitoring, that the inputted light is signal light, further determines based on a spectral line shape of the inputted light, when the power thereof does not reach the saturation level, whether the inputted light is the signal light or ASE light; and stops a transfer of the ASE light if determined to be the ASE light.

Abstract: A transponder for performing bidirectional conversion between a client-side signal used for communication to a client device and a transmission path-side signal used for communication to a transmission path, the transponder comprising: a client-side interface for inputting/outputting the client-side signal; a transmission path-side interface for inputting/outputting the transmission path-side signal; a connection determining unit for determining which of the another client-side interface and the client device is coupled to the client-side interface; and a transmission signal generating unit for outputting, in a case where a state signal indicating a state on a transmission path side is input to the transmission path-side interface, a transmission signal indicating that the state signal has been input, from the client-side interface, wherein: the transmission signal generating unit changes a form of the transmission signal to be output from the client-side interface, based on a determination result obtained by

Abstract: Methods and apparatus for control of variable optical attenuators are described. A method for control of a variable optical attenuator located in an optical link comprising a plurality of optical attenuators. The method comprises determining that an initial calibration step of a variable optical attenuator has been completed, and transmitting a signal indicative of the variable optical attenuator having completed the initial calibration step for receipt by a downstream variable optical attenuator. A method of controlling a variable optical attenuator comprises receiving a signal indicative of an upstream variable optical attenuator having completed an initial calibration step, and initiating calibration of the variable optical attenuator in response to receipt of said signal.

Abstract: A network component comprising at least one processor configured to implement a method comprising obtaining a wavelength availability information for a path, determining whether to implement a wavelength assignment based on the wavelength availability information, updating the wavelength availability information when the wavelength assignment is to be implemented, and forwarding the wavelength availability information. Also included is a method comprising obtaining a wavelength availability information, comparing a number of wavelengths in the wavelength availability information to a threshold, determining whether to implement wavelength conversion along a path when the number of available wavelengths is less than or about equal to the threshold, and resetting the wavelength availability information when wavelength conversion is to be implemented.

Abstract: An apparatus and method for automatic power adjustment of an optical network system are provided by the present invention. In the automatic power adjustment system which includes a plurality of electric-adjustable optical attenuators and a power adjustment module configured in a network management board: each OA board, i.e. optical amplification board and each service forwarding board respectively report their power relevant parameters to the power adjustment module; the power adjustment module judges whether an adjustment is required for an OA board and/or a service forwarding board after performing calculation according to the power parameters reported by each OA board and each service forwarding board, and when determining that the adjustment is required, triggers the adjustable optical attenuator on the corresponding OA board and/or the service forwarding board to perform the power adjustment.

Abstract: An optical communication system supporting detection and communication networks. A communication network transmission path and the detection network transmission path are provided as separate paths established by separate fibers or fiber pairs of the same optical fiber cable. All of the elements coupled to the communication network transmission path and the detection network transmission path may be powered by the same power feed equipment through the same optical fiber cable power conductor.

Abstract: The invention provides an optoelectronic processing apparatus and methods for processing constraint information. The optoelectronic processing apparatus is applied to the optical transport network OTN device, and comprises: a 3R regeneration unit for reamplifying, reshaping and retiming a signal; a wavelength conversion unit for performing wavelength conversion to the signal; an interlayer adapting unit for converting the signal between the OCh layer and the ODUk layer; and a dispatching unit for dispatching the 3R regeneration unit, the wavelength conversion unit and the interlayer adapting unit according to a function identification parameter of the optoelectronic processing apparatus so as to process the signal. By the present invention, the management of the OTN device is simplified, and the 3R regeneration, wavelength conversion and optoelectronic interlayer adaptation information are managed uniformly.

Abstract: A relay station has an optical switch that switches a reception path of an optical signal. The relay station generates a subsignal that has a wavelength different from the wavelength of a data signal corresponding to a signal to be transmitted and transmits an optical signal obtained by multiplexing the generated subsignal and the data signal. In this state, when the data signal is not included in the received optical signal, the relay station determines whether the subsignal is included in the optical signal. When it is determined that the subsignal is included, the relay station maintains a connection path of the optical switch without switching the connection path.

Abstract: A computer system and method for transmitting LAN signals over transport systems. LAN signals are generated in any client LAN compliant interface. A transceiver receives the client LAN signal in the LAN format. The client LAN signals are not converted to a SONET transmission format at any time before reaching the transceiver. The transceiver then converts the client LAN signal to an internal electrical LAN signal before re-clocking the internal electrical LAN signal. The re-clocked internal electrical LAN signal is then re-modulated into a second LAN signal. The second LAN signal is then transmitted to a transport system.

Abstract: Disclosed is an optical amplifier which includes an upward optical amplifier configured to amplify an input upward optical signal of an input optical signal; and a control circuit configured to control an operation of the upward optical amplifier according to whether an upward stream is detected from the input upward optical signal.

Abstract: An optical transmission apparatus includes a reception part for receiving a wavelength division multiplexed (WDM) signal reached via optical amplifiers; a measuring part for measuring an optical power level of each wavelength of the WDM signal received by the reception part; a determination part for determining whether an amount of tilt of the WDM signal calculated based on measurement results of the measuring part is suitable or not; an operation part for calculating the tilt correction amount to be applied to tilt correction processing performed by the optical amplifiers if the amount of tilt of the WDM signal is not suitable; and a notification part for notifying the optical amplifiers of the tilt correction amount.

Abstract: A method for arranging relay stations in an optical transmission system including relay stations arranged so that optical signals at a first transmission speed can be transmitted from a transmission end to a reception end, includes: judging whether a transmission of optical signals at a second transmission speed different from the first transmission speed in a section connecting arbitrary two of the relay stations where a regenerative repeater station capable of regenerating optical signals can be arranged is possible; determining a combination of sections judged to be capable of performing transmission that enables a transmission of optical signals from the transmission end to the reception end; and making both ends of respective sections of the determined combination be the relay stations where the regenerative repeater station is arranged, wherein the judging includes a judgment condition which is satisfied in a section including sections but unsatisfied in one of the sections.

Abstract: A wavelength division multiplexing (WDM)-time division multiplexing (TDM) passive optical network (PON) remote terminal (RT) is provided. The wavelength division multiplexing (WDM)-time division multiplexing (TDM) passive optical network (PON) remote terminal (RT), includes: a WDM-TDM converter configured to convert a WDM downstream optical signal that is received from a central office terminal (COT) into a TDM downstream optical signal or to convert a TDM upstream optical signal that is received from an optical network terminal (ONT) into a WDM upstream optical signal; an error detector configured to detect an error; and a controller configured to, in response to an error being detected, transmit the WDM upstream optical signal to the COT via a first standby link or transmit the TDM downstream optical signal to the ONT via a second standby link.

Abstract: An optical amplifier using the evanescent light to control the optical output level is provided. The optical amplifier includes: a waveguide path transmitting an optical signal; an optical amplification unit formed on the waveguide path and amplifying the optical signal by an excitation light; an irradiation unit irradiating the excitation light to the optical amplification unit; an optical detection unit generating an electric signal which corresponds to a detected light; a branching unit branching an evanescent light being the optical signal outputted from the optical amplification unit and leaked outside the waveguide path, and focusing the evanescent light on the optical detection unit; a wavelength detection unit detecting a wavelength multiplicity of the optical signal based on the detected evanescent light; and a light amount adjustment unit adjusting a light amount of the excitation light irradiated by the irradiation unit based on the wavelength multiplicity.

Abstract: There is provides a wavelength conversion apparatus for converting a wavelength of input signal light and for outputting output signal light of the converted wavelength. The apparatus includes a first and a second nonlinear mediums. The first nonlinear medium receives a first input light and outputs a first output light having a wavelength which is longer than that of the first input light, the wavelength being dependent on optical power of the first input light. The second nonlinear medium receives a second input light and a light output by a light source and outputs a second output light having a wavelength dependent on the wavelengths of the second input light and the light. The first output light is input as the second input light to the second nonlinear medium or the second output light is input as the first input light to the first nonlinear medium.

Abstract: Embodiments of the present invention relate to systems and methods for distributing an intentionally skewed optical-clock signal to nodes of a source synchronous computer system. In one system embodiment, a source synchronous system comprises a waveguide, an optical-system clock optically coupled to the waveguide, and a number of nodes optically coupled to the waveguide. The optical-system clock generates and injects a master optical-clock signal into the waveguide. The master optical-clock signal acquiring a skew as it passes between nodes. Each node extracts a portion of the master optical-clock signal and processes optical signals using the portion of the master optical-clock signal having a different skew for the respective extracting node.

Abstract: A method for performing an optical line analysis of continuous data signals transmitted in a passive optical network (PON). The method comprises determining, from an optical signal of the optical line, at least one of a phase early/late indicator based on a phase position of an input continuous data signal relative to sampling clock signals, a difference phase indicator based on an input phase control code, and a low frequency jitter indicator based on an input phase control code; computing a plurality of statistical measures regarding frequency and amplitude components of a jitter of the input continuous data signal, wherein the statistical measures are computed based on one of the phase early/late information indicator, the difference phase indicator, and the low frequency jitter indicator; and analyzing the plurality of statistical measures to detect optical failures in the PON and determining a root cause of each of the detected failures.

Abstract: An optical relay system is provided, which includes a first optical signal distribution device (101), a phase detection device (103), an amplitude regeneration device (102), and a phase regeneration and load device (104). An optical relay method is further provided, which includes the following steps. A received input signal is divided into two paths; phase information of one path of the input signal is extracted, and is converted to an amplitude modulated signal; an amplitude of the other path of the input signal is restored, so as to generate an amplitude regenerated signal; a phase is loaded on the amplitude regenerated signal by using the amplitude modulated signal, so as to generate a phase regenerated signal. The system and method eliminate a phase noise of the signal in a transmission process, improve a transmission performance of the signal, and realize a simple implementation method.

Abstract: The path selection and wavelength assignment to a selected path are performed by mapping the wavelength reach to the demand distribution (agile reach) resulting in a 50-60% increase in the network reach. The network reach is further increased (about 2.2 times) when on-line measured performance data are used for path selection and wavelength assignment. The connections may be engineered/upgraded individually, by optimizing the parameters of the entire path or of a regenerator section of the respective path. The upgrades include changing the wavelength, adjusting the parameters of the regenerator section, controlling the launch powers, mapping a certain transmitter and/or receiver to the respective wavelength, selecting the wavelengths on a certain link so as to reduce cross-talk, increasing wavelength spacing, etc.

Abstract: A relay apparatus including: a first interface 11 that branches an optical signal that is input in a first direction from one side of the optical transmission line, and directs the optical signal to a first path and a second path, the first path being a processing path of an optical signal having a first transmission speed, the second path being a processing path of an optical signal having a second transmission speed that is different from the first transmission speed; a processing section 12 that executes processing on an optical signal propagating through each of the paths in accordance with a corresponding transmission speed; and a second interface 13 that binds the first path and the second path of the optical signal on which the processing is executed by the processing section, by means of wavelength multiplexing and directs to the other end of the optical transmission line.

Abstract: A system and method for Raman amplification of optical signals in a wavelength division multiplexing (WDM) optical transmission system includes transmitting optical signals within a transmission band via an optical waveguide between a transmitter and a receiver, Raman-amplifying the optical signals with at least one pump so as to distort an amplification profile of the Raman amplification within the transmission band, and rectifying the distorted amplification profile so as to compensate for the distortion.

Abstract: An amplifier node, in an optical network, includes a first switch connected to a working path from which network traffic is received; a second switch connected to the working path to which the network traffic is transmitted; and two amplifiers that interconnect the first switch and the second switch, where the network traffic travels from the first switch to the second switch via a first amplifier. The amplifier node also includes a controller to receive an instruction to switch the network traffic from the first amplifier to a second amplifier that enables the first amplifier to be repaired; send, to the first switch and the second switch, another instruction to switch the network traffic from the first amplifier to the second amplifier; receive an indication that the network traffic is traveling via the second amplifier; and send a notification that the first amplifier can be repaired based on the indication.