12 wavelengths CWDM is coarse wavelength multiplexing/demultiplexing module combined with optical switch. Support bidirectional 12 CWDM wavelengths and each wavelength has PD for optical power detection. The COM port supports primary and backup optical path switching and bidirectional optical power detection.
Semi-active WDM: Passive colorful optical modules and multiplexer/demultiplexer units are deployed at AAU side, and active WDM equipment is deployed at DU side. Multiple AAUs share a fiber for transmission, and no power supply is required at the remote end.
In 4G era, because of low requirements for protection and monitoring, passive CWDM has been widely used due to its mature industry chain, power-free, and plug-and-play features. However, after entering 5G era, in the face of the contradiction between the high reliability of 2B service, the management of massive CRAN networks, and the limited number of operation and maintenance personnel, the application of semi-active technology has become a solution for how to meet new requirements of 5G era.
Semi-active CWDM is based on passive CWDM,adding coupler, optical switch and PD core unit to realize line protection and local side optical power detection functions.