Single-fiber bidirectional optical ring system, method for controlling single-fiber bidirectional optical ring system, and central station

A single-fiber bidirectional optical ring system comprising:

• a central station;
• one or more slave stations to perform single-fiber bidirectional communication with the central station;
• and
• a network in which the central station and the one or more slave stations are connected in a ring shape by optical fibers, wherein
• the central station includes:
• a first single-fiber bidirectional optical transceiver connected in a clockwise direction of the network, the first single-fiber bidirectional optical transceiver outputting a downstream optical signal of a second wavelength and receiving an upstream optical signal of a first wavelength output from the one or more slave stations;
• a second single-fiber bidirectional optical transceiver connected in a counterclockwise direction of the network, the second single-fiber bidirectional optical transceiver outputting a downstream optical signal of the second wavelength and receiving an upstream optical signal of the first wavelength output from the one or more slave stations;
• and
• first time synchronization control circuitry to adjust timings at which the first single-fiber bidirectional optical transceiver and the second single-fiber bidirectional optical transceiver output the downstream optical signals of the second wavelength, and cause the first single-fiber bidirectional optical transceiver and the second single-fiber bidirectional optical transceiver to output the downstream optical signals of the second wavelength in different time slots into which a predetermined cycle is divided.