Abstract: Optical transmission system transmits WDM signal from first node to second node via optical fiber. The optical transmission system includes: first OCM that detects optical power of each wavelength channel of the WDM signal in the first node; second OCM that detects optical power of each wavelength channel of the WDM signal in the second node; first processor that calculates linear SNR of each wavelength channel based on the optical power of each wavelength channel detected by the second OCM; second processor that calculates non-linear SNR of each wavelength channel based on the optical power of each wavelength channel detected by the first OCM; third processor that calculates GSNR for each wavelength channel using the linear SNR and the non-linear SNR; and fourth processor that controls transmission power of each wavelength channel of the WDM signal based on the GSNR of each wavelength channel.

Abstract: A forward Raman amplifier includes a plurality of pumping light sources with different wavelengths and the forward Raman amplifier, according to a fiber type or a zero-dispersion wavelength of the fiber, changes the number of pumping light sources to be emitted, changes a power ratio between the plurality of pumping light sources with the different wavelengths or changes wavelength characteristics of a gain, according to a fiber type.

Abstract: An optical transmission system includes a first optical node, a second optical node, and an optical fiber provided between the first optical node and the second optical node. The optical transmission system further includes: a signal generator provided in the first optical node and configured to generate an optical signal including a plurality of wavelength channels and an empty channel; an optical transmission circuit provided in the first optical node and configured to output the optical signal to the optical fiber; an optical channel monitor provided in the second optical node and configured to measure reception power of each channel in the optical signal received through the optical fiber; and a processor configured to determine a type of the optical fiber based on the reception power of the empty channel, the reception power being measured by the optical channel monitor.

Abstract: A Raman amplifier includes a first light source that outputs a primary pumping light, which propagates in a same direction as a propagation direction of a signal light, to an optical transmission line for Raman amplification, a second light source that outputs a secondary pumping light, which pumps and amplifies the primary pumping light and propagates in the same direction as the propagation direction, to the optical transmission line, and a control unit that controls a gain for the signal light by adjusting power of the secondary pumping light.

Abstract: An optical transmission system includes a first optical node, a second optical node, and an optical fiber provided between the first optical node and the second optical node. The optical transmission system further includes: a signal generator provided in the first optical node and configured to generate an optical signal including a plurality of wavelength channels and an empty channel; an optical transmission circuit provided in the first optical node and configured to output the optical signal to the optical fiber; an optical channel monitor provided in the second optical node and configured to measure reception power of each channel in the optical signal received through the optical fiber; and a processor configured to determine a type of the optical fiber based on the reception power of the empty channel, the reception power being measured by the optical channel monitor.

Abstract: Optical transmission system transmits WDM signal from first node to second node via optical fiber. The optical transmission system includes: first OCM that detects optical power of each wavelength channel of the WDM signal in the first node; second OCM that detects optical power of each wavelength channel of the WDM signal in the second node; first processor that calculates linear SNR of each wavelength channel based on the optical power of each wavelength channel detected by the second OCM; second processor that calculates non-linear SNR of each wavelength channel based on the optical power of each wavelength channel detected by the first OCM; third processor that calculates GSNR for each wavelength channel using the linear SNR and the non-linear SNR; and fourth processor that controls transmission power of each wavelength channel of the WDM signal based on the GSNR of each wavelength channel.

Abstract: A wavelength converter that converts signal light and pump light into a light containing a new wavelength component using a nonlinear optical fiber, has a PBS for splitting incident light into a first polarized wave and a second polarized wave, a first polarization controller provided between the PBS and a first end of the nonlinear optical fiber, and a second polarization controller provided between the PBS and a second end of the nonlinear optical fiber, wherein in an optical loop connecting the PBS, the first polarization controller, the nonlinear optical fiber and the second polarization controller, the first polarized wave and a first component of the pump light travel through the nonlinear optical fiber in a first direction, and the second polarized wave and a second component of the pump light travel through the nonlinear optical fiber in a second direction opposite to the first direction.

Abstract: A wavelength converter that converts signal light and pump light into a light containing a new wavelength component using a nonlinear optical fiber, has a PBS for splitting incident light into a first polarized wave and a second polarized wave, a first polarization controller provided between the PBS and a first end of the nonlinear optical fiber, and a second polarization controller provided between the PBS and a second end of the nonlinear optical fiber, wherein in an optical loop connecting the PBS, the first polarization controller, the nonlinear optical fiber and the second polarization controller, the first polarized wave and a first component of the pump light travel through the nonlinear optical fiber in a first direction, and the second polarized wave and a second component of the pump light travel through the nonlinear optical fiber in a second direction opposite to the first direction.

Abstract: A method includes multiplexing signal light of first polarization and excitation light, and multiplexing signal light of second polarization, which is perpendicular to the first polarization, and the excitation light, modulating the signal light of the first polarization before the wavelength conversion, and reducing a modulation component in signal light after wavelength conversion, modulating the signal light of the second polarization before the wavelength conversion, and reducing the modulation component in the signal light after the wavelength conversion, and multiplexing the signal light of the first polarization after the wavelength conversion and the signal light of the second polarization after the wavelength conversion.

Abstract: A wavelength converter includes an input port, an optical fiber configured to cause a signal light and an excitation light to interact with each other due to a nonlinear optical effect, the signal light and the excitation light being input to the input port, a stress application mechanism configured to apply stress in a direction crossing a winding direction of the optical fiber, and an output port configured to output a converted light having a wavelength different from wavelengths of the signal light and the excitation light.

Abstract: A wavelength converter includes an excitation light source outputting excitation light, a beam splitter receiving an input of the excitation light and an input of the optical signal and to divide both the inputted excitation light and the inputted optical signal into a first polarization component and a second polarization component, a non-linear optical fiber as a non-polarization-maintaining fiber, an accommodation section securing and accommodating the non-linear optical fiber, a first collimator lens disposed between the beam splitter and a first end of the non-linear optical fiber, and a second collimator lens disposed between the beam splitter and a second end of the non-linear optical fiber, wherein the optical signal is inputted to the beam splitter from a direction different from the input of the excitation light.

Abstract: A wavelength converter includes a first phase modulator configured to perform phase modulation on pump light in accordance with a first phase modulation signal, a second phase modulator configured to perform phase modulation on signal light in accordance with a second phase modulation signal, a wavelength converter configured to multiplex the signal light having undergone the phase modulation with the pump light having undergone the phase modulation, the wavelength converter configured to perform wavelength conversion on the signal light in accordance with the pump light, a detector configured to detect a modulation component from the signal light having undergone the phase modulation and the pump light having undergone the phase modulation, and a generator configured to generate the first phase modulation signal and the second phase modulation signal so as to minimize the detected modulation component.

Abstract: A method includes multiplexing signal light of first polarization and excitation light, and multiplexing signal light of second polarization, which is perpendicular to the first polarization, and the excitation light, modulating the signal light of the first polarization before the wavelength conversion, and reducing a modulation component in signal light after wavelength conversion, modulating the signal light of the second polarization before the wavelength conversion, and reducing the modulation component in the signal light after the wavelength conversion, and multiplexing the signal light of the first polarization after the wavelength conversion and the signal light of the second polarization after the wavelength conversion.

Abstract: An optical transmission apparatus includes a wavelength variable filter whose transmission light wavelength is variable; a receiver that receives light, the light being sent from another optical transmission apparatus and passing through the wavelength variable filter; a transmitter that sends to the another optical transmission apparatus, a utilization permission request for a second wavelength corresponding to a first wavelength of the light received by the receiver, the transmitter sending the utilization permission request as light of the second wavelength and in a form of a tone signal of a predetermined frequency; and a controller that, when receiving from the another optical transmission apparatus, a utilization permission notification of the second wavelength for a sender of the utilization permission request, configures a wavelength of a main signal to the second wavelength, the main signal being sent from the transmitter to the another optical transmission apparatus.

Abstract: A transmission device includes an interface configured to acquire, from a base band unit having a communication destination that is one of remote radio heads, communication destination information relating to the remote radio head of the communication destination, a receiver configured to receive signals of given wavelength from optical termination devices, and a transmitter configured to transmit a first signal that includes wavelength information indicative of the given wavelength and the communication destination information to optical termination devices, wherein, when the receiver receives, from an optical termination device of the remote radio head of the communication destination from among optical termination devices, a second signal of the given wavelength according to the first signal, the receiver sets, between the receiver and the optical termination device, a relay path that relays communication between the base band unit and the remote radio head of the communication destination.

Abstract: A wavelength converter includes an excitation light source outputting excitation light, a beam splitter receiving an input of the excitation light and an input of the optical signal and to divide both the inputted excitation light and the inputted optical signal into a first polarization component and a second polarization component, a non-linear optical fiber as a non-polarization-maintaining fiber, an accommodation section securing and accommodating the non-linear optical fiber, a first collimator lens disposed between the beam splitter and a first end of the non-linear optical fiber, and a second collimator lens disposed between the beam splitter and a second end of the non-linear optical fiber, wherein the optical signal is inputted to the beam splitter from a direction different from the input of the excitation light.

Abstract: A wavelength converter includes a first phase modulator configured to perform phase modulation on pump light in accordance with a first phase modulation signal, a second phase modulator configured to perform phase modulation on signal light in accordance with a second phase modulation signal, a wavelength converter configured to multiplex the signal light having undergone the phase modulation with the pump light having undergone the phase modulation, the wavelength converter configured to perform wavelength conversion on the signal light in accordance with the pump light, a detector configured to detect a modulation component from the signal light having undergone the phase modulation and the pump light having undergone the phase modulation, and a generator configured to generate the first phase modulation signal and the second phase modulation signal so as to minimize the detected modulation component.

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: A transmission device includes an interface configured to acquire, from a base band unit having a communication destination that is one of remote radio heads, communication destination information relating to the remote radio head of the communication destination, a receiver configured to receive signals of given wavelength from optical termination devices, and a transmitter configured to transmit a first signal that includes wavelength information indicative of the given wavelength and the communication destination information to optical termination devices, wherein, when the receiver receives, from an optical termination device of the remote radio head of the communication destination from among optical termination devices, a second signal of the given wavelength according to the first signal, the receiver sets, between the receiver and the optical termination device, a relay path that relays communication between the base band unit and the remote radio head of the communication destination.

Abstract: An optical transmission apparatus includes a wavelength variable filter whose transmission light wavelength is variable; a receiver that receives light, the light being sent from another optical transmission apparatus and passing through the wavelength variable filter; a transmitter that sends to the another optical transmission apparatus, a utilization permission request for a second wavelength corresponding to a first wavelength of the light received by the receiver, the transmitter sending the utilization permission request as light of the second wavelength and in a form of a tone signal of a predetermined frequency; and a controller that, when receiving from the another optical transmission apparatus, a utilization permission notification of the second wavelength for a sender of the utilization permission request, configures a wavelength of a main signal to the second wavelength, the main signal being sent from the transmitter to the another optical transmission apparatus.