Optical communication system and optical communication method

An optical communication method applied to an optical communication system including a first network-side device and a second network-side device each coupled to a communication network, and a first terminal-side device and a second terminal-side device configured to communicate with the first network-side device and the second network-side device by being coupled to the first network-side device and the second network-side device via a first communication cable and a second communication cable, respectively, the optical communication method comprising:

• coupling the first network-side device to the first terminal-side device via the communication network, the second network-side device, and a third communication cable for coupling the second network-side device and the first terminal-side device so as to communicate between the first network-side device and the first terminal-side device;
• and
• switching a state between a first state in which the first network-side device is coupled to the second terminal-side device via a fourth communication cable for coupling the first network-side device and the second terminal-side device, and a second state in which the first network-side device is coupled to the first terminal-side device via the third communication cable coupling the communication network to the second network-side device.