Active DWDM VS Passive DWDM Network

As you know, passive DWDM is a Dense Wavelength Division Multiplexing optical system that operates without powered components. 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.

Active DWDM mux demux can take in 8/16/32 etc channels all on the same wavelength (1310nm) and them shift them all to different individual frequencies before muxing them onto a single fiber. They can be demuxed at the other end all back to the same frequency (1310nm) again.

Active DWDM

Advantages
Active DWDM can fit a lot more wavelengths/colors onto a single fiber pair. The pro being, the composite signal that is sent over a single fiber pair can carry more bandwidth than a passive of the same size could, in turn you don't need as much physical fiber between your two sites (this really only applies if you require that much bandwidth). This is advantageous when distance is a problem because it allows you to get more out of a single leased fiber pair as opposed to passive.

Active setups grant you more control over your optical network, you can dynamically re-tune wavelengths without dropping connections (it's transparent to whatever is riding on that wavelength).

Scalability - Active can be easier to scale as your network grows (you can fit more wavelengths on the fiber).

Disadvantages
Expensive - Active DWDM setups are extremely expensive in comparison to passive, if you don't need that long distance requirements, not choose active DWDM.

Setup/Configuration - Depending on your vendor, configuration can be a serious undertaking, and require a solid understanding of optical networks. There are many more components in active builds. DWDM necessarily requires transponders, further, after muxing the signals, they typically need active amplification to have any interesting reach. Without this, you're only going a (relatively) short distance.

Passive DWDM


Advantages
Cheaper compared to active DWDM - As mentioned above, less components are required, and less engineering time is required.

Initial Setup - Because of the colored optics there isn't a need to tune wavelengths for all of your connections. It's a matter of matching your colored optics and plugging it.

Disadvantages
Scalability - Not only are you limited to colored optics, and thus less wavelengths on the transport fiber as you grow you would be require to have more passive devices. Furthermore, with the more passive devices you have the more difficult it can be to manage, you'll have to start managing the same wavelength on multiple passive devices and they could be serving different purposes on each depending on your setup.

Control - If you need to change a wavelength or connection for whatever reason, you're option is limited to taking it out of service and disconnecting the physical cabling as the wavelength is tied to the optic.

From the above, you must have deeply know the comparision between active DWDM and passive DWDM Network.