Erbium-Doped Fiber Amplifier (EDFA) in DWDM System
DWDM is a transmission technology in optical fiber communication. It uses one optical fiber to transmit multiple optical carrier signals of different wavelengths at the same time, and divides the wavelength range used by the optical fiber into several channels. The channel transmits optical signals. Therefore, DWDM has greatly improved the transmission capacity of the optical communication system. The appearance of Erbium-doped fiber amplifier ( EDFA ) makes DWDM optical signal transmission farther. 1. Introduction to the principle of EDFA Erbium (Er) is a rare earth element. When making an optical fiber, a certain proportion of erbium element is added to form an erbium-doped optical fiber, which has the effect of amplification. Erbium ions have three working energy levels: E1, E2 and E3. Among them, E1 has the lowest energy level and is called the ground state; E2 is the metastable state; E3 has the highest energy level and becomes the excited state. In the case of not be...