At present, optical fiber routing protection technology mainly includes optical recovery section protection, optical self-healing ring protection and optical fiber line automatic protection (OLP) technology. Among them, the protection of the light recovery segment is for the whole process of the light recovery segment, but not for each optical circuit (such as end station to OA station and OA station to OA station). Moreover, because 1+1 protection is generally adopted, the insertion loss is relatively large (>5dB). The protection of optical self-healing ring requires the whole network equipment to form a ring. When the business in one direction is blocked, the business will detour to the target site from the opposite direction. The disadvantage of this scheme is that the network is required to reserve the bandwidth required by the business detour, which leads to high investment.

The automatic protection technology of optical fiber line is a simple and feasible solution with reliable operation. It can complete the switch protection from the main route to the standby route within 30ms, which can effectively prevent the interruption of optical cable caused by municipal construction and other projects, and then cause network interruption.

Optical switches at both ends are connected to two optical cable lines of different routes by optical switches at both ends. Under normal circumstances, optical switches at both ends are selected as the main line. Meanwhile, OLP equipment can monitor the standby line in real time, and timely send an alarm if there is any abnormal situation, reminding the owner to repair as soon as possible, so as to ensure that the standby line is available. However, when the main fiber optic cable failure increases beyond the switching threshold, the optical switch at both ends will be synchronously switched to the standby line to ensure the normal operation of the system.

The OLP device has an independent network management, which can monitor the attenuation of the optical cable line, the luminous power and luminous power of the device in real time and intuitively. In addition, the network administrator also has the function of short message cat, which can timely inform relevant personnel of specific alarm information according to customer requirements. Since the OLP adopts optical switch at both ends to realize the selection, the intervention loss of the original line is relatively low, generally lower than 3dB, and the intervention loss of the superior OLP can reach less than 1dB. As the data room transmission distance is not far, the increased loss will not affect the normal operation of the system. In addition, since the switching basis is the attenuation of optical cable line, it has nothing to do with the equipment manufacturer and the system speed. Moreover, the equipment is compatible with all the equipment manufacturers and can also meet the requirements of various systems with different rates. For example, SDH/PTN and DWDM/OTN can be protected, and GE and 10G protection can also be applied to 40G and 100G protection. This means that when the devices on both ends are upgraded, the OLP devices do not need to be upgraded, but only need to adjust the relevant threshold according to different systems.