Abstract: 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.

Abstract: An optical communication device that communicates with another optical communication device by using at least a time division multiplexing system, the optical communication device including: a management control signal division unit that divides a management control signal used for management and control; and a transmission unit that transmits the management control signal divided, by including the management control signal divided in a burst signal to be transmitted at an assigned transmission timing.

Abstract: One aspect of the present invention is a receiving apparatus including a reception unit that receives signal light frequency-modulated by a signal obtained by adding a main signal and a control signal having a lower frequency than the main signal, and converts the signal light into an analog electric signal, and a processing unit that acquires a code sequence corresponding to the control signal on the basis of the analog electric signal, in which the processing unit includes a frequency offset amount acquisition unit that acquires a frequency offset amount of the signal light acquired on the basis of the analog electric signal, and a determination unit that determines the code sequence corresponding to the control signal on the basis of the frequency offset amount acquired by the frequency offset amount acquisition unit.

Abstract: An optical line terminal includes a communication unit configured to communicate with a plurality of optical network units, and a control unit configured to dynamically change at least one of a time width of a specific period and a cycle of the specific period, the specific period being a period in which an authentication request signal is received from the new optical network unit via the communication unit.