Monitoring of relay node in optical transmission system
An aspect of the present invention is an optical transmission system in which one or more optical transmitters and one or more optical receivers perform communication via an optical transmission path, the optical transmission path including a plurality of relay nodes including optical amplifiers that amplify optical signals, the one or more optical transmitters transmitting optical signals at a plurality of channel frequencies, the one or more optical receivers estimating variations in intensities of the optical systems on the optical transmission path for each of the plurality of channel frequencies, the optical transmission system including: a network controller that acquires estimation information indicating a result of estimating the variations from the one or more optical receivers and acquires gain spectra of the optical amplifiers in the optical transmission path on the basis of the acquired plurality of pieces of estimation information.
1 . An optical transmission system in which one or more optical transmitters and one or more optical receivers perform communication via an optical transmission path,
wherein the optical transmission path includes a plurality of relay nodes including optical amplifiers that amplify optical signals,
the one or more optical transmitters transmit optical signals at a plurality of channel frequencies,
the one or more optical receivers estimate variations in intensities of the optical signals on the optical transmission path for each of the plurality of channel frequencies, and
the optical transmission system comprises:
a network controller that acquires estimation information indicating a result of estimating the variations from the one or more optical receivers and acquires gain spectra of the optical amplifiers in the optical transmission path on the basis of the acquired estimation information.
2 . The optical transmission system according to claim 1 ,
wherein the one or more optical transmitters are a plurality of optical transmitters configured to transmit optical signals at mutually different channel frequencies, and
the one or more optical receivers are a plurality of optical receivers which receive a respective optical signal transmitted by an optical transmitter associated with the optical receiver itself and estimate the variations in intensity of the received respective optical signal on the optical transmission path.
3 . The optical transmission system according to claim 1 ,
wherein the one or more optical transmitters are a plurality of optical transmitters configured to transmit optical signals while sweeping a frequency band that is different from the other optical transmitters, and
the one or more optical receivers are a plurality of optical receivers which receive a respective optical signal transmitted by an optical transmitter associated with the optical receiver itself and estimate variations in intensity of the received respective optical signal on the optical transmission path for each channel frequency swept in the frequency band.
4 . The optical transmission system according to claim 1 ,
wherein the network controller acquires the gain spectra at positions in accordance with positions of the relay nodes on the optical transmission path on the basis of the estimation information acquired from the one or more optical receivers.
5 . The optical transmission system according to claim 1 ,
wherein the network controller compensates for a gain tilt of each relay node through feedback control based on the acquired gain spectra.
6 . The optical transmission system according to claim 5 ,
wherein the network controller adjusts pump wavelengths or pump powers of the optical amplifiers of the relay nodes such that the gain spectra of the relay nodes have a predetermined shape through the feedback control or levels the intensities of the optical signal at each channel frequency by causing inverse functions of the gain spectra to act on wavelength selection functions of the relay nodes.
7 . An optical transmission method comprising, in an optical transmission system in which one or more optical transmitters and one or more optical receivers perform communication via an optical transmission path:
by the optical transmission path, amplifying optical signals by optical amplifiers in a plurality of relay nodes and relaying the optical signals;
by the one or more optical transmitters, transmitting optical signals at a plurality of channel frequencies;
by the one or more optical receivers, estimating variations in intensities of the optical signals on the optical transmission path for each of the plurality of channel frequencies; and
by a network controller, acquiring estimation information indicating a result of estimating the variations from the one or more optical receivers and acquiring gain spectra of the optical amplifiers in the optical transmission path on the basis of the acquired estimation information.