Abstract: A transmission apparatus including: a branch circuit that branches a signal including first data and second data superimposed on the first data into two signals; a limiting amplifier that amplifies one signal in the two signals; a linear amplifier that amplifies another signal in the two signals; a first detector that detects the first data from the amplified one signal; and a second detector that detects the second data from the amplified another signal and the amplified one signal.

Abstract: An optical transmitting apparatus includes a variable optical attenuator of a magneto-optical effect type disposed by spatial coupling between a light source and an optical fiber, the variable optical attenuator configured to attenuate light output from the light source and coupled to the optical fiber, according to an input driving voltage; a generator configured to generate the driving voltage of the variable optical attenuator based on information to be superimposed on the light by the variable optical attenuator, the generator inputting the generated driving voltage into the variable optical attenuator; and a controller configured to control a bias of the driving voltage generated by the generator, the controller controlling an amplitude of the driving voltage generated by the generator, based on data according to characteristics between the driving voltage and an attenuation amount of the light by the variable optical attenuator.

Abstract: An optical communication system includes an optical transmitter, a plurality of optical receivers, and a splitter that splits light transmitted by the optical transmitter to the plurality of optical receivers. The optical transmitter includes a variable-wavelength light source capable of transmitting light of a first wavelength and light of a third wavelength between the first wavelength and a second wavelength. A first optical receiver of the plurality of optical receivers includes a first optical filter having a first transmission band including the first and third wavelengths, and a first receiving unit that receives light having passed through the first optical filter. A second optical receiver of the plurality of optical receivers includes a second optical filter having a second transmission band including the second and third wavelengths, and a second receiving unit that receives light having passed through the second optical filter.

Abstract: A processor of an optical transport apparatus is configured to transport an optical multiplexed signal between the optical transport apparatus and a counterpart apparatus by using a plurality of communication units; transmit an arbitrary optical wavelength from the optical multiplexed signal passing through ports by using a wavelength selective switch that has the ports respectively connected to the communication units; control a radio unit in the counterpart apparatus so as to change a frequency of the radio signal in the specified optical wavelength; and change a transmission band of the port through which the optical wavelength passes, according to a change of the frequency of the radio signal. The processor is configured to control an optical transmission unit of the counterpart apparatus so as to change a center wavelength of an optical wavelength passing through the port to a center wavelength of the changed transmission band of the port.

Abstract: There is provided an apparatus configured to estimate optical transmission performance in a transmission path of an optical signal, the apparatus including a memory, and a processor coupled to the memory and the processor configured to acquire a first index related to a first transmission performance of an optical signal transmitted through a span group between a first node and an n-th node and a second index related to a second transmission performance of an optical signal transmitted through a span or a span group between the first node and an m-th node, wherein n is an integer of 3 or more, and m is the integer satisfying m<n, and estimate a third index related to a third transmission performance of an optical signal to be transmitted through a span between the m-th node and the n-th node, based on the first index and the second index.

Abstract: An optical terminal device includes: a relay processing circuitry relaying communication between first base stations, respectively connected to optical terminating devices at branch destinations of a transmission path, and a control device controlling the first base stations in accordance with information acquired from a second base station covering a cell overlapping cells of the first base stations; a detecting circuitry detecting a sleep control instruction, issued for one of the first base stations from the control device, from the communication being relayed by the relay processing circuitry; and a control circuitry performing control, via the transmission path, to cause the optical terminating device connected to the one of the first base stations to shift to an operating state or a sleep state, which consumes less power than the operating state, in response to detection of the sleep control instruction, the optical terminating device being one of the optical terminating devices.

Abstract: An optical receiver receives signal light obtained by superimposing a second signal to a first signal according to a predetermined superimposition pattern. In the optical receiver, a tunable optical filter allows a part of a spectrum of the received light to pass, and a photodetector converts the transmission light into an electrical signal. A filter controller controls a center transmittance frequency of the tunable optical filter in response to a superimposed period and a non-superimposed period of the second signal identified based on the electrical signal. A superimposed signal detector detects the second signal based on the electrical signal obtained in response to the control of the tunable optical filter during the superimposed period. An optical signal-to-noise ratio (OSNR) calculator calculates an OSNR of the signal light based on the electrical signal obtained in response to the control of the tunable optical filter during the non-superimposed period.

Abstract: An optical transmitting apparatus includes a variable optical attenuator of a magneto-optical effect type disposed by spatial coupling between a light source and an optical fiber, the variable optical attenuator configured to attenuate light output from the light source and coupled to the optical fiber, according to an input driving voltage; a generator configured to generate the driving voltage of the variable optical attenuator based on information to be superimposed on the light by the variable optical attenuator, the generator inputting the generated driving voltage into the variable optical attenuator; and a controller configured to control a bias of the driving voltage generated by the generator, the controller controlling an amplitude of the driving voltage generated by the generator, based on data according to characteristics between the driving voltage and an attenuation amount of the light by the variable optical attenuator.

Abstract: A transmission apparatus including: a branch circuit that branches a signal including first data and second data superimposed on the first data into two signals; a limiting amplifier that amplifies one signal in the two signals; a linear amplifier that amplifies another signal in the two signals; a first detector that detects the first data from the amplified one signal; and a second detector that detects the second data from the amplified another signal and the amplified one signal.

Abstract: An optical receiver includes: a tunable filter configured to partially transmit a wavelength-multiplexed optical-signal including a first optical-signal having a first wavelength, a second optical-signal having a second wavelength, and a third optical-signal having a third wavelength, with a frequency-modulated signal superimposed on each of the first to third optical-signals; a photo detector configured to detect an optical-power of the wavelength-multiplexed optical-signal transmitted through the tunable filter; and a superimposed signal detector configured to detect the frequency-modulated signal superimposed on the first optical-signal, based on an amplitude-modulated signal according to a variation in the optical-power on a first filter setting where both of the first optical-signal and the second optical-signal transmit through the tunable filter, and an amplitude-modulated signal according to a variation in the optical-power on a second filter setting where both of the first optical-signal and the thir

Abstract: There is provided an apparatus configured to estimate optical transmission performance in a transmission path of an optical signal, the apparatus including a memory, and a processor coupled to the memory and the processor configured to acquire a first index related to a first transmission performance of an optical signal transmitted through a span group between a first node and an n-th node and a second index related to a second transmission performance of an optical signal transmitted through a span or a span group between the first node and an m-th node, wherein n is an integer of 3 or more, and m is the integer satisfying m<n, and estimate a third index related to a third transmission performance of an optical signal to be transmitted through a span between the m-th node and the n-th node, based on the first index and the second index.

Abstract: A processor of an optical transport apparatus is configured to transport an optical multiplexed signal between the optical transport apparatus and a counterpart apparatus by using a plurality of communication units; transmit an arbitrary optical wavelength from the optical multiplexed signal passing through ports by using a wavelength selective switch that has the ports respectively connected to the communication units; control a radio unit in the counterpart apparatus so as to change a frequency of the radio signal in the specified optical wavelength; and change a transmission band of the port through which the optical wavelength passes, according to a change of the frequency of the radio signal. The processor is configured to control an optical transmission unit of the counterpart apparatus so as to change a center wavelength of an optical wavelength passing through the port to a center wavelength of the changed transmission band of the port.

Abstract: An optical communication system includes an optical transmitter, a plurality of optical receivers, and a splitter that splits light transmitted by the optical transmitter to the plurality of optical receivers. The optical transmitter includes a variable-wavelength light source capable of transmitting light of a first wavelength and light of a third wavelength between the first wavelength and a second wavelength. A first optical receiver of the plurality of optical receivers includes a first optical filter having a first transmission band including the first and third wavelengths, and a first receiving unit that receives light having passed through the first optical filter. A second optical receiver of the plurality of optical receivers includes a second optical filter having a second transmission band including the second and third wavelengths, and a second receiving unit that receives light having passed through the second optical filter.

Abstract: A communication device that receives received signal light from another communication device, the communication device includes: a receiver configured to receive signal light output from an optical filter that outputs signal light of a given wavelength included the received signal light; and a transmitter configured to transmit, to the another communication device, a control signal for controlling a wavelength of laser light for use in generation of the signal light of the given wavelength, wherein the receiver is configured to detect power of the signal light output from the optical filter; and the transmitter is configured to set, when the signal light is not successfully received in the receiver, the control signal so as to cause the another communication device to control the wavelength of the laser light, based on the power.

Abstract: An optical receiver receives a wavelength multiplexed optical signal including wavelength channels. A superimposition signal is superimposed by frequency modulation on each of the wavelength channels. The optical receiver includes: an optical filter that filters the wavelength multiplexed optical signal; a filter controller that controls a wavelength of a transmission band of the optical filter; a photo detector that generates an intensity signal representing a change in the intensity of an output light of the optical filter; an signal detector that detects, according to the intensity signal, a superimposition signal superimposed on a specified wavelength channel. The filter controller controls the wavelength of the transmission band so that the amplitude of the intensity signal is larger, and then controls the wavelength of the transmission band so that the number of errors in the superimposition signal detected by the signal detector is reduced.

Abstract: An optical transmission device includes: a plurality of optical transceivers; a wavelength selective switch; and a controller configured to control the plurality of optical transceivers and the wavelength selective switch. Each of the optical transceivers includes a wavelength tunable light source. The controller controls a wavelength of a wavelength tunable light source of a selected optical transceiver according to a wavelength of an optical signal received by the destination remote device. The controller controls the wavelength selective switch so as to generate the WDM optical signal from a plurality of optical signals generated by the plurality of optical transceivers, and to guide the plurality of optical signals received from the plurality of remote devices to the plurality of optical transceivers according to wavelengths of the received plurality of optical signals.

Abstract: An optical transmission apparatus includes a first optical transmission line through which the signal of the first channel pass, the signal having a signal quality at a first strength and; an optical receiver configured to receive, from a network control apparatus, information about a second strength based on a signal quality of a signal of a second channel passing through a second optical transmission line of which at least a portion is a same as that of the signal of the first channel; and an optical transmitter configured to transmit the signal of the first channel at the second strength.

Abstract: An optical receiver receives signal light obtained by superimposing a second signal to a first signal according to a predetermined superimposition pattern. In the optical receiver, a tunable optical filter allows a part of a spectrum of the received light to pass, and a photodetector converts the transmission light into an electrical signal. A filter controller controls a center transmittance frequency of the tunable optical filter in response to a superimposed period and a non-superimposed period of the second signal identified based on the electrical signal. A superimposed signal detector detects the second signal based on the electrical signal obtained in response to the control of the tunable optical filter during the superimposed period. An optical signal-to-noise ratio (OSNR) calculator calculates an OSNR of the signal light based on the electrical signal obtained in response to the control of the tunable optical filter during the non-superimposed period.

Abstract: An optical receiver includes: a tunable filter configured to partially transmit a wavelength-multiplexed optical-signal including a first optical-signal having a first wavelength, a second optical-signal having a second wavelength, and a third optical-signal having a third wavelength, with a frequency-modulated signal superimposed on each of the first to third optical-signals; a photo detector configured to detect an optical-power of the wavelength-multiplexed optical-signal transmitted through the tunable filter; and a superimposed signal detector configured to detect the frequency-modulated signal superimposed on the first optical-signal, based on an amplitude-modulated signal according to a variation in the optical-power on a first filter setting where both of the first optical-signal and the second optical-signal transmit through the tunable filter, and an amplitude-modulated signal according to a variation in the optical-power on a second filter setting where both of the first optical-signal and the thir

Abstract: A device for monitoring optical signal includes: an optical filter configured to allow part of a spectrum of an optical signal on which a frequency or phase modulated signal is superimposed to pass; and a detection unit configured to detect signal quality of the optical signal, based on a power ratio of a signal component to a noise component of the modulated signal, the power ratio being obtained based on a power change in accordance with the modulated signal of light that has been caused to pass through the optical filter.