What does WDM (Wavelength Division Multiplexing )stand for?

This article will include these subject.
What does WDM stand for?
The basic structure of WDM system
Advantages of WDM technology
What does Mux and Demux stand for?
The difference between WDM and optical splitter
The indicators that affect the WDM devices
How to understand the O, E, S, C, L, U band
What does CWDM stand for vs. DWDM, FWDM, LWDM, MWDM?

What does WDM stand for?
Wavelength Division Multiplexing(WDM) is one of the most common way of using wavelengths to increase bandwidth by multiplexing various optical carrier signals onto a single optical fiber. It combines a series of optical carrier signals with different wavelengths carrying various information and coupled to the same optical fiber for transmission at the transmitting end. At the receiving end, optical signals of various wavelengths are separated by a demultiplexer. This technique of simultaneously transmitting two or many different wavelengths in the same fiber is called wavelength division multiplexing, or WDM.