Abstract: There is provided a management device configured to manage a plurality of optical nodes in an optical transmission system, the management device including a memory, and a processor coupled to the memory and the processor configured to specify a relay node on a path relaying a traffic in the optical transmission system among the plurality of optical nodes, designate a candidate wavelength of a candidate for a target of transmitting through the traffic in the specified relay node from wavelengths being used in the specified relay node, determine whether or not the designated candidate wavelength is usable in an optical node of the plurality of optical nodes to terminate the traffic, and set the candidate wavelength in the relay node, as a wavelength used to transmit through the traffic, when it is determined that the designated candidate wavelength is usable in the optical node to terminate the traffic.

Abstract: There is provided a management device configured to manage a plurality of optical nodes in an optical transmission system, the management device including a memory, and a processor coupled to the memory and the processor configured to specify an optical node to terminate a traffic in the optical transmission system, determine whether or not a first optical component that does not use a wavelength being used in a second optical component included in the specified optical node exists in the specified optical node, determine whether or not a path that makes the wavelength usable exists in the optical transmission system when it is determined that the first optical component exists in the specified optical node, and set the wavelength and the path that makes the wavelength usable in the first optical component when it is determined that the path making the wavelength usable exists in the specified optical node.

Abstract: A digital coherent receiver that receives a first optical signal in a WDM optical signal includes: a front-end circuit configured to generate a digital signal indicating the first optical signal; a waveform distortion corrector configured to generate a correction result signal indicating a first optical signal whose waveform distortion has been corrected by performing a digital arithmetic operation on the digital signal using at least one dispersion compensators and at least one nonlinear compensators; and a controller configured to adjust operation states of specified dispersion compensators among the plurality of dispersion compensators and specified nonlinear compensators among the plurality of nonlinear compensators. The number of the specified dispersion compensators and the number of the specified nonlinear compensators are determined based on the number of spans of an optical transmission line through which the first optical signal is transmitted.

Abstract: An optical transmission device includes: a monitor configured to monitor a power of an input optical signal and detect a spectrum of the input optical signal; a detector configured to detect a wavelength division multiplexed optical signal that includes a plurality of carriers continuously allocated at a specified frequency spacing based on the spectrum of the input optical signal; a generator configured to generate adjustment information that specifies an attenuation amount in a frequency range in which the wavelength division multiplexed optical signal is allocated; and a power adjustment device configured to adjust powers of respective carriers multiplexed in the wavelength division multiplexed optical signal according to the adjustment information generated by the generator.

Abstract: A transmitter to be added or reduced turns ON/OFF an optical output. A relay station and a receiving terminal station acquire the amount of fluctuation of the optical output of the received signal light when the optical output of the added transmitter is turned ON and OFF. From the amount of fluctuation of the optical output, the number of wavelengths after the addition or reduction is acquired. Without an OSC signal, each station may be informed of the number of wavelengths. Therefore, the configuration for transmitting and receiving the OSC signal is not requested, thereby reducing the total cost, appropriately controlling the gain of the optical amplifier, and successfully maintaining transmission quality.

Abstract: A digital coherent receiver that receives a first optical signal in a WDM optical signal includes: a front-end circuit configured to generate a digital signal indicating the first optical signal; a waveform distortion corrector configured to generate a correction result signal indicating a first optical signal whose waveform distortion has been corrected by performing a digital arithmetic operation on the digital signal using at least one dispersion compensators and at least one nonlinear compensators; and a controller configured to adjust operation states of specified dispersion compensators among the plurality of dispersion compensators and specified nonlinear compensators among the plurality of nonlinear compensators. The number of the specified dispersion compensators and the number of the specified nonlinear compensators are determined based on the number of spans of an optical transmission line through which the first optical signal is transmitted.

Abstract: An optical receiving device includes: an optical amplifier configured to amplify a wavelength multiplexed optical signal; a demultiplexer configured to demultiplex the amplified wavelength multiplexed signal into optical signals of a plurality of wavelengths; optical receivers configured to regenerate the demultiplexed optical signals; error correction units configured to correct a bit error in the regenerated optical signals; and main control unit. The control unit adjusts RXDTV of the optical receiver for receiving optical signals of a given wavelength to the optimal value in the state where the gain of the optical amplifier is lowered from that of a normal operation such that the occurrence of bit errors in the optical signals of the other wavelengths does not exceed the correction capability of the error correction unit.

Abstract: An optical receiving apparatus includes a variable dispersion compensation unit, a delay interference unit, a photoelectric converter, a polarization control unit for control the polarization state of an optical signal inputted to the photoelectric converter, a received data processing unit for monitoring the number of error occurrences, and a control unit for controlling the dispersion compensation amount at the variable dispersion compensation unit and the optical phase control amount at the delay interference unit, based on information on the number of error occurrences from the received data processing unit.

Abstract: An optical receiving apparatus includes a variable dispersion compensation unit, a delay interference unit, a photoelectric converter, a polarization control unit for control the polarization state of an optical signal inputted to the photoelectric converter, a received data processing unit for monitoring the number of error occurrences, and a control unit for controlling the dispersion compensation amount at the variable dispersion compensation unit and the optical phase control amount at the delay interference unit, based on information on the number of error occurrences from the received data processing unit.

Abstract: An optical receiving apparatus is provided with a receiver, a setting unit, and a storage unit. The receiver receives an optical signal modulated in a DPSK format and performs variable dispersion compensation and delay interference processing on the optical signal to demodulate the optical signal. The setting unit sets suitable setting values of the variable dispersion compensation and the delay interference processing for the receiver based on an error condition of the demodulated signal. The storage unit stores the setting values set by the setting unit.

Abstract: The optical transmitter and receiver of the invention includes: a variable dispersion compensator that performs wavelength dispersion compensation on an optical signal of a differential M-phase modulation format input from a transmission path; an optical amplifier that compensates an optical loss in the variable dispersion compensator; a delay interferometer that delays and interference processes the optical signal output from the optical amplifier; and a photoelectric conversion circuit that photoelectric converts the output light from the delay interferometer to generate a demodulated electric signal. The output level of the optical amplifier is decreased at the time of start up to deteriorate the OSNR of the optical signal input to the photoelectric conversion circuit, to thereby realize a state in which an error occurs more easily, and then optimization control of the variable dispersion compensator and the delay interferometer is started.

Abstract: An optical signal, which is a low-speed signal superimposed on a high-speed phase modulated optical signal by intensity modulation, is used. In an optical receiver apparatus 40, a received signal is split, and one of the split signals is O/E converted and low frequency component alone is extracted via a filter 46. A clock is extracted from low-frequency component by CDR, and is compared with a preset frequency. Using the frequency difference obtained, dispersion compensation is performed with low accuracy. Next, the amount of phase control of the delay interferometer 21 is adjusted so that the amplitude of the electrical signal is maximized. An error rate is measured, and fine adjustment is performed to improve the error rate.

Abstract: A transponder in a wavelength division multiplexing apparatus detects a wavelength of a leak light (received light) having one of plural wavelengths multiplexed or divided by a WDM unit, the leak light having been received from the WDM unit when the transponder is connected to the WDM unit; determines a transmission wavelength which is a wavelength of a light to be transmitted to the WDM unit on the basis of the wavelength of the received light; and sets to convert the wavelength of the light to be transmitted to the WDM unit into the transmission wavelength, and transmit the converted light.

Abstract: Spectral components of input signal light is partially removed by allowing the input signal light regulated to predetermined power to pass through an optical filter, and the rate of the input signal light is identified in response to the power of the signal light passing through the optical filter.

Abstract: The optical transmitter and receiver of the invention includes: a variable dispersion compensator that performs wavelength dispersion compensation on an optical signal of a differential M-phase modulation format input from a transmission path; an optical amplifier that compensates an optical loss in the variable dispersion compensator; a delay interferometer that delays and interference processes the optical signal output from the optical amplifier; and a photoelectric conversion circuit that photoelectric converts the output light from the delay interferometer to generate a demodulated electric signal. The output level of the optical amplifier is decreased at the time of start up to deteriorate the OSNR of the optical signal input to the photoelectric conversion circuit, to thereby realize a state in which an error occurs more easily, and then optimization control of the variable dispersion compensator and the delay interferometer is started.

Abstract: An optical receiving apparatus is provided with a receiver, a setting unit, and a storage unit. The receiver receives an optical signal modulated in a DPSK format and performs variable dispersion compensation and delay interference processing on the optical signal to demodulate the optical signal. The setting unit sets suitable setting values of the variable dispersion compensation and the delay interference processing for the receiver based on an error condition of the demodulated signal. The storage unit stores the setting values set by the setting unit.

Abstract: An optical signal, which is a low-speed signal superimposed on a high-speed phase modulated optical signal by intensity modulation, is used. In an optical receiver apparatus 40, a received signal is split, and one of the split signals is O/E converted and low frequency component alone is extracted via a filter 46. A clock is extracted from low-frequency component by CDR, and is compared with a preset frequency. Using the frequency difference obtained, dispersion compensation is performed with low accuracy. Next, the amount of phase control of the delay interferometer 21 is adjusted so that the amplitude of the electrical signal is maximized. An error rate is measured, and fine adjustment is performed to improve the error rate.

Abstract: A transmitting unit of a transponder transmits a signal light having a wavelength which is set according to a control unit to a WDM unit. In this situation, when the wavelength of the signal light is adapted to a pass wavelength of an optical filter to which the signal light is inputted, the signal light is returned to a transmitting origin through a loopback path formed within the WDM unit, and then received by a receiving unit. The control unit determines the wavelength that has been setting in the transmitting unit when the signal light is received as a transmission wavelength to be used by the transponder.

Abstract: A transponder in a wavelength division multiplexing apparatus detects a wavelength of a leak light (received light) having one of plural wavelengths multiplexed or divided by a WDM unit, the leak light having been received from the WDM unit when the transponder is connected to the WDM unit; determines a transmission wavelength which is a wavelength of a light to be transmitted to the WDM unit on the basis of the wavelength of the received light; and sets to convert the wavelength of the light to be transmitted to the WDM unit into the transmission wavelength, and transmit the converted light.