With the rapid growth of data services mainly based on IP services, the demand for network bandwidth is becoming higher and higher. The dynamic allocation of network bandwidth is becoming more and more urgent. The network is required to develop in the direction of high capacity, intelligence and dynamic configuration. In the DWDM system, ROADM can be conveniently configured and will be widely used in the DWDM system. It will dynamically change wavelength resource allocation, meet the business needs of dynamic configuration. The optical transponder is a key part of it, transforming the non-standard wavelength optical signal into the DWDM standard wavelength optical signal. It performs performance monitoring and protection switching on the wavelength channel. Therefore, the research on its performance and implementation has important practical value. The optical repeater has the following functions:
1. It is possible to add and drop wavelengths selectively on demand, and each add and drop of wavelength does not affect the pass-through wavelength. This ensures that cascaded OADMs are used as much as possible without regeneration.
2. The optical transponder has a wavelength conversion function to realize an open structure so that the network has wavelength compatibility and service transparency. When adding and dropping wavelengths, it can flexibly switch between the non-standard wavelengths that carry local services and the DWDM standard wavelengths.
3. The optical transponder has the power equalization capability. It must effectively control the power of the pass-through wavelength and the local wavelength to compensate for link loss.
4. The optical transponder can manage the wavelength, handle the overhead, and be ordered and controlled remotely or locally.
5. It meets the conventional requirements of optical communication for the transmission of optical signals, such as the maximum signal-to-noise ratio OSNR, power consistency, and optical loss requirements.
The entire ROADM system is mainly composed of the following parts: line processing part, performance monitoring part, add or drop multiplexing part, optical transponder, and network element monitoring part. The line processing part mainly completes power amplification, equalization, and line protection of the main optical channel signal. The performance monitoring part monitors the multi-wavelength optical signals on the optical fiber line, extracting relevant performance parameters and reporting them to the equipment monitoring unit. The interpolation and multiplexing part is responsible for the implementation of down, through and up operation of several single wavelength signals in a multi-wavelength optical signal. The optical transponder converts the non-standard wavelength optical signal of the client layer equipment into the DWDM standard wavelength optical signal. The network element monitoring part monitors various functional modules and environmental conditions in the node equipment and provides external network management interfaces.