DWDM is an optical technology for optical fiber, which can increase the bandwidth of existing fiber backbone network. Due to its large capacity, high survivability and flexibility, DWDM technology is very common in backbone network and long-distance transmission. However, in practice, problems such as fiber failure and line interruption may affect the communication and services carried by optical fiber. Therefore, a secure DWDM Network is needed to solve these problems.
Optical line protection (OLP)
OLP is used to protect optical network transmission line. It can realize optical power monitoring and automatic switching of optical lines. In optical communication network, OLP monitors the optical power of optical fiber and standby fiber in real time. When the optical power of the current optical fiber is less than the preset switching threshold, an alarm will be triggered and the flow will be automatically switched to the standby optical fiber in less than 15 ms to protect the optical transmission system lines. It should be noted that the length of the primary link and the backup link must be similar. When there are enough dark fibers, OLP is the ideal choice for backbone network. There are different types of OLP devices. The most commonly used OLP are OLP 1:1 and OLP 1 + 1.
Optical power detection (OPD)
OPD is a kind of optical power monitoring equipment, which has the characteristics of high monitoring accuracy and wide range of optical power monitoring. It is suitable for the loss measurement of optical passive components such as optical fiber and optical cable, as well as the construction and maintenance of optical fiber communication system. It mainly has 1310nm / 1550nm monitoring light. It can detect and monitor the links which can find service faults in real time.
Optical performance monitoring (OPM)
In DWDM Network, OPM is mainly used to monitor the quality of data channel by measuring its optical characteristics in real time. Remote transmission involving DWDM networks contains many components that may degrade the strength of optical signals. The longer the fiber optic cable is, the more likely the signal strength will be affected. Therefore, it is important to deploy OPMS as strategic points along the way, as they ensure high-quality optical signals and data integrity. However, the use of OPM is limited to C-band.
Ring network protection
Take the three-point ring network as an example. The business of one site can be transferred clockwise or anticlockwise to another site. In this case, if the optical fiber between the two sites is cut off, the service can be run normally by sending the data in the opposite direction to the destination.
Comprehensive protection
This method is very suitable when the budget is sufficient and there are too many fibers. The purpose is to make sure that once the link is disconnected, it can switch to the redundant allocated capacity in a certain period of time, so as to ensure the normal operation. In case of failure or failure, it is feasible to use the redundant part of the network to provide network capacity, especially in point-to-point DWDM Network, because sometimes the failure of equipment, fiber or node is not uncommon, resulting in huge revenue loss. Moreover, more effectively, OLP (optical line protection) is also more expensive.
