In optimizing, or maximizing, the use of the fiber multiplexer, sometimes referred to as a mux, is the major key. In the operation, the multiplexer lie is a major part, and to be transported simultaneously over a single fiber, it gathers all the data streams together. It is performed by taking multiple input signals and then combining, multiplexing them into a single, common line output. On a single fiber or fiber pair, the multiplexed signal can now be transmitted over the optical network. The streams are demultiplexed.
Hence multiplexers make you split one single cable into multiple traffic channels and simultaneously transport multiple data channels over it. In terms of the volume of traffic and the type of data, you want to transmit you get more flexibility.
How Multiplexer combines channels to transmit multiple services with the use of fiber
Multiplexing and DE multiplexing are commonly referred to as DWDM mux/demux modules because they are usually all done within the same type of module. As they need no power and are passive modules they take up little space that is ideal for the interconnectivity of green data center. In the analogy of road, the multiple input signals that are put into multiplexers can be considered as the lines on the road that separate the different lanes of traffic.
Over a pair of fibers, the early WDM systems were able to transport two bi-directional channels. There has been a rapid evolution of the technology and there is an increase seen in both the number of channels and the amount of data per channel transported. Today, at any one time typically 40 or 80 channels in metro networks are simultaneously transmitted down a dark fiber pair and PLC splitter also used.
Optical add-drop multiplexers
CWDM or DWDM multiplexers are referred to as terminal muxes because at the endpoints in a network they are positioned. So if there is a need to connect only two sites then a multiplexer is positioned at each site and between the two sites a point-to-point connection is created. You will frequently observe that networks have additional sites where connectivity is required of some, but not all the traffic.
Original source: https://fibermart.blogspot.com/
