The bypass is an optical path control device that can be used to protect optical devices from faults (power outages, hardware failures, abnormal lighting, software deadlocks, etc.) by bypassing this node and ensuring that the network is not affected. It can automatically identify the power supply status, optical signal output status, and software operation status of network nodes, and has functions such as power failure bypass, no optical bypass, and no heartbeat signal bypass. Mainly used for protecting flow control equipment, repeater optical equipment, etc.