Optical communication system, control apparatus and quality compensation method
An optical switch having a plurality of ports outputs an optical signal, which is input from one of the plurality of ports, from another port. A quality compensator perform quality compensation of the optical signal output from the optical switch, and input the quality-compensated optical signal to the optical switch. A controller selects, among the plurality of quality compensators, a quality compensator that performs quality compensation according to the degree of quality deterioration of the optical signal when the optical signal input from a predetermined port of the optical switch is transmitted through a transmission path. The controller controls the optical switch so that the optical signal, in which quality is compensated by the selected quality compensator through the optical signal input from the predetermined port being output to the selected quality compensator, is output from the port corresponding to a transmission destination of the optical signal.
1 . An optical communication system comprising:
an optical switch having a plurality of ports and outputting an optical signal, which is input from a port among the plurality of ports, from another port;
a plurality of quality compensators that perform quality compensation of the optical signal output from the optical switch and input the quality-compensated optical signal to the optical switch, the plurality of quality compensators being connected in parallel to the optical switch; and
when a plurality of subscriber devices, which are different, are separately connected to ports of the plurality of ports of the optical switch, a controller that performs, for each of the plurality of subscriber devices, processing of selecting, among the plurality of quality compensators, a quality compensator that performs quality compensation according to a degree of quality deterioration of the optical signal when the optical signal input from the port connected to a subscriber device is transmitted through a transmission path, and processing of controlling the optical switch so that the optical signal, in which quality is compensated by the selected quality compensator through the optical signal input from the port connected to the subscriber device being output to the quality compensator selected for the subscriber device, is output from a port corresponding to a transmission destination of the optical signal.
2 . The optical communication system according to claim 1 , wherein
the controller selects the quality compensator among the plurality of quality compensators, based on a combination of a cumulative chromatic dispersion amount of the transmission path assigned to the optical signal input from the port connected to the subscriber device and a degree of quality deterioration allowable for the optical signal based on characteristics of the optical signal.
3 . The optical communication system according to claim 2 , wherein
the controller acquires the cumulative chromatic dispersion amount of the transmission path based on a distance and chromatic dispersion of the transmission path, and the degree of quality deterioration allowable based on a value of a signal parameter that determines the characteristics of the optical signal including a wavelength of the optical signal, and selects the quality compensator based on the combination of the cumulative chromatic dispersion amount of the transmission path and the degree of quality deterioration allowable for the optical signal.
4 . A control apparatus comprising:
a selector that selects, for each of a plurality of subscriber devices which are different, a quality compensator that performs quality compensation of an optical signal according to a degree of quality deterioration of the optical signal when the optical signal input from a port connected to a subscriber device is transmitted through a transmission path, among a plurality of quality compensators connected in parallel to a optical switch, when the plurality of subscriber devices are separately connected to ports of a plurality of ports of the optical switch, the optical switch having the plurality of ports and outputting the optical signal, which is input from the port among the plurality of ports, from another port; and
an instructor that instructs the optical switch so that the optical signal, in which quality is compensated by the selected quality compensator through the optical signal input from the port connected to the subscriber device being output to the quality compensator selected for the subscriber device, is output from a port corresponding to a transmission destination of the optical signal.
5 . The control apparatus according to claim 4 , further comprising:
an allocator that allocates a wavelength and a transmission path used for the optical signal from the subscriber device to the transmission destination in response to a request from the subscriber device, wherein
the selector selects for each of the plurality of subscriber devices, among the plurality of quality compensators, the quality compensator that performs compensation according to the degree of quality deterioration of the optical signal when the optical signal of the wavelength allocated by the allocator is transmitted through the transmission path allocated by the allocator, and
the instructor instructs the optical switch so that the optical signal, in which the quality is compensated by the selected quality compensator through the optical signal of the wavelength input from the port connected to the subscriber device begin output to the quality compensator selected by the selector, is output from the port connected to the transmission path allocated by the allocator.
6 . The control apparatus according to claim 5 , wherein
the selector selects, among the plurality of quality compensators, the quality compensator that performs quality compensation according to the degree of quality deterioration allowed for the optical signal input from the port connected to the subscriber device, and the degree of quality deterioration allowed for the optical signal corresponds to one or both of a resource used for transmission of the optical signal and a value of a signal parameter used in the optical signal transmitter to control characteristics of the optical signal.
7 . The control apparatus according to claim 6 , wherein
the resource is one or both of the transmission path through which the optical signal is transmitted and a device that relays the optical signal.
8 . The control apparatus according to claim 4 , wherein
the degree of quality deterioration of the optical signal when the optical signal is transmitted through the transmission path corresponds to a length of the transmission path,
the instructor selects for each of the plurality of subscriber devices, among the plurality of quality compensators, the quality compensator that performs quality compensation of the optical signal based on the length of the transmission path through which the optical signal input from the port connected to the subscriber device is transmitted, and
the length of the transmission path is estimated based on a round-trip time measured by transmitting and receiving an optical signal via the transmission path between the subscriber device and the transmission destination.
9 . The control apparatus according to claim 8 , wherein
the optical signal used for measuring the round trip time is a control signal that is superimposed on a main signal and is slower than the main signal.
10 . The control apparatus according to claim 8 , wherein the instructor selects for each of the plurality of subscriber devices, among the plurality of quality compensators, a plurality of candidates for the quality compensator that performs quality compensation of the optical signal based on the length of the transmission path through which the optical signal input from the port connected to the subscriber device is transmitted, selects the quality compensator that performs quality compensation of the optical signal among the plurality of candidates, and selects the quality compensator which has not been selected among the plurality of candidates when quality of the optical signal that is compensated by the selected quality compensator is lower than a predetermined value.
11 . The control apparatus according to claim 4 , wherein
the selector selects, for each of the plurality of subscriber devices, one or more quality compensators for performing quality compensation among the plurality of quality compensators, and
the instructor controls the optical switch so that the optical signal input from the port connected to the subscriber device, in which two or more quality compensators are selected, being sequentially output to the two or more quality compensators selected for the subscriber device, and the optical signal, in which quality is compensated by all the selected quality compensators, is output from the port corresponding to the transmission destination of the optical signal.
12 . The control apparatus according to claim 4 , wherein
the quality compensator performs one or both of dispersion compensation of an optical signal and amplification of the optical signal.
13 . The control apparatus according to claim 4 , wherein
the selector selects the quality compensator among the plurality of quality compensators, based on a combination of a cumulative chromatic dispersion amount of the transmission path assigned to the optical signal input from the port connected to the subscriber device and a degree of quality deterioration allowable for the optical signal based on characteristics of the optical signal.
14 . The control apparatus according to claim 13 , wherein
the selector acquires the cumulative chromatic dispersion amount of the transmission path based on a distance and chromatic dispersion of the transmission path, and the degree of quality deterioration allowable based on a value of a signal parameter that determines the characteristics of the optical signal including a wavelength of the optical signal, and selects the quality compensator based on the combination of the cumulative chromatic dispersion amount of the transmission path and the degree of quality deterioration allowable for the optical signal.
15 . A quality compensation method comprising:
selecting, for each of a plurality of subscriber devices which are different a quality compensator that performs quality compensation of an optical signal when the optical signal input from a port connected to a subscriber device is transmitted through a transmission path among a plurality of quality compensators connected in parallel to a optical switch, when the plurality of subscriber devices are separately connected to ports of a plurality of ports of the optical switch, the optical switch having the plurality of ports and outputting the optical signal, which is input from the port among the plurality of ports, from another port; and
instructing the optical switch so that the optical signal, in which quality is compensated by the selected quality compensator through the optical signal input from the port connected to the subscriber device being output to the quality compensator selected for the subscriber device, is output from a port corresponding to a transmission destination of the optical signal.