In principle, CWDM uses optical multiplexer to multiplex optical signals of different wavelengths to a single optical fiber for transmission. At the receiving end of the link, with the help of optical demultiplexer, the mixed signals in the optical fiber are decomposed into signals of different wavelengths and connected to the corresponding receiving equipment.
Advantage
The most important advantage of CWDM is the low cost of equipment. Another advantage of CWDM is that it can reduce the operation cost of the network. Because of the small size, low power consumption, simple maintenance and convenient power supply of CWDM equipment, 220V AC power supply can be used. Due to its small number of wavelengths, the amount of board card backup is small. CWDM system can significantly improve the transmission capacity of optical fiber and the utilization of optical fiber resources.
Another advantage of CWDM is its small size and low power consumption. The simplified laser module in CWDM system reduces the volume of the integrated optical transceiver module, and the simplified equipment structure also reduces the volume of the equipment and saves the room space. CWDM has good flexibility and scalability. For metropolitan area business, the flexibility of service provision, especially the speed of service provision and the ability to expand with the development of business are very important. Because of the above advantages of CWDM Technology, CWDM has been widely used in telecommunication, radio and television, enterprise network, campus network and other fields.
Insufficient
The biggest problem of CWDM Technology is that its cost advantage over DWDM equipment is still not obvious. At present, the number of optical channels (wavelengths) supported by CWDM equipment is no more than 8, mainly due to the immature manufacturing process of E-band optical transceiver module. In addition, the g.652c optical cable, which eliminates the water absorption peak, is less used in the current network, so the market demand for E-band optical transceiver module is not large. There are still many technical problems in CWDM system with higher rate and longer transmission distance. Such as the dispersion of 10G system, ultra wideband optical amplification technology and so on. In addition, the standardization process needs to be accelerated, especially the guidance of operators in terms of business interface functions
