As the phenomenon of optical fiber interruption caused by engineering construction is widespread, how to avoid the emergence of major accidents has become a top priority. At present, optical cable routing protection technologies mainly include optical multiplexing section protection, optical self-healing ring protection, and optical fiber line automatic protection (OLP). Among them, the optical multiplex section protection is to protect the entire optical multiplex section, but cannot protect each section of optical lines (such as end station to OA station, OA station to OA station), and because 1+1 protection is generally adopted, the insertion loss is relatively large (>5dB). Optical self-healing ring protection requires the entire network equipment to form a ring. When the service in one direction is blocked, the service 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 for the detour of the service. As a result, the investment is high, and there are also compatibility issues with equipment from different manufacturers.
The optical fiber line automatic protection technology is a simple, easy-to-use and reliable solution. It can complete the switch protection from the main route to the backup route within 30ms, and can effectively prevent the optical cable from being interrupted due to municipal construction and other projects and thus avoid the further network interruption.
The transmission and reception of the equipment at both ends are connected to two optical cable lines of different routes by optical switches. Under normal circumstances, the optical switches at both ends select the main line. At the same time, the OLP optical line protection equipment can monitor the standby line in real time, and will sound a warning in time if there is an abnormal situation so as to remind the owner to repair it as soon as possible to ensure that the backup line is available. When the attenuation of the main optical cable exceeds the switching threshold, the optical switches at both ends will be synchronized to the standby line to ensure that the system can continue to operate normally.
The OLP optical line protection equipment has an independent network management, which can monitor the attenuation of the optical cable line, the luminous power of the equipment, and the received optical power in real time and intuitively. In addition, the network management is also equipped with a short message modem function, which can notify relevant personnel of specific alarm information in a timely manner through short messages according to customer requirements. Since optical switches are used at both ends of the OLP to achieve selective transmission and reception, the insertion loss of the original line is relatively low, which is generally lower than 3dB, and the insertion loss of the superior OLP can reach within 1dB. Since the transmission distance of the data room is not long, the increased loss will not affect the normal operation of the system. In addition, because the switching basis is the attenuation of the optical cable line, it has nothing to do with the equipment manufacturer and the system rate, and the equipment is compatible with all manufacturers' equipment, and can also meet various systems with different speeds. For example, it can protect SDH/PTN and DWDM/OTN as well, and it can be used for GE, 10G protection or 40G, 100G protection. This means that when the devices at both ends are upgraded, the OLP devices do not need to be upgraded. Only adjust the relevant thresholds according to different systems.