A brief introduction on the basic principles, structural, functional configuration, critical technical components and technical characteristics of optical wavelength division multiplexing systems to explain WDM system is the developing direction of the future development of optical communication.
I. Optical Wavelength Division Multiplexing (WDM) Technology
The optical WDM (Wavelength Division Multiplexing) technology is that the optical carrier signal can be transmitted in an optical fiber by different wavelength waves and each optical carrier signal can carry multiplexed analog or multi-channel digital signals by FDM or TDM. The basic principle is the different wavelengths of light signals are combined on the transmit side (Mux), and are coupled to be transmitted on the same fiber in the fiber optic line, then separated from the signals of different wavelengths in the receiving end (Demax), and for further processing to recover the original signal into a different terminal. Therefore, this technique is called optical wavelength division multiplexing, referred to as the optical wavelength division multiplexing technology. WDM technology has great importance on updating the network expansion, developing the broadband services, and mining fiber bandwidth capacity to achieve ultra-high-speed communications. Especially WDM coupled with erbium-doped fiber amplifier (EDFA) has more powerful appeal on modern information network.