I am trying to understand the cross-over point for when I would deploy active DWDM over passive DWDM (as active seems to be more expensive based on my initial research);
Passive DWDM takes in various colours / wavelengths and muxes them onto a single fibre pair. This seems to be the same principal as a CWDM mux/demux, however with DWDM we know, we can get a lot more channels. (Also I believe that with CWDM we are using different frequencies within the ITU grid?)
Active DWDM can take in 8/16/32 etc channels all on the same wavelength (say 1310nm) and them shift them all to different individual frequencies before muxing them onto a single fibre. They can be demuxed at the other end all back to the same frequency again (say 1310nm).
So am I correct that the reasons for deploying active DWDM over passive are that
- Active can provide more channels
- Active can use all the same input frequency, thereby any 1310nm device can connect to it, without the need for tuned/coloured optics?
Have I missed any pro's of active over passive? What are the con's?