Electronic doped fiber amplifier. Concept made into law in 1984 Modified Final Judgement (MFJ) that all long distance carriers must have the same access to local facilities as AT&T Electronic serial number (ESN) A 32-bit code that is unique to each mobile unit. Used to validate mobile.

an optical amplifier that amplifies a light signal for propagation across long-distance fiber networks

Erbium doped fiber amplifier. EDFAs are used for amplifying optical signals in long-haul optical networks. Unlike electro-optic repeaters, which convert light to electricity, amplify the signal, and then reconvert it to light, EDFAs amplify the light signal itself. EDFAs have advantages that make them critical components of optical networks: they are fast, very simple, and are not frequency-dependent, meaning that networks may be upgraded by installing new wavelength division multiplexing (WDM) equipment without changing fiber or amplifiers between nodes.