Erbium-Doped Fiber Amplifiers for Optical Fiber Communications

The field of erbium-doped fiber amplifiers (EDFA) [1-4] has expanded rapidly, from the developments in rare-earth-doped fiber fabrication [5-8], to the more recent demonstration of practical laser-diode pumped devices [9-11]. Because of their many advantages, it is likely that EDFA’s will contribute to significant progress in future 1.5μm optical fiber communication systems [12]. The interest of using optical amplifiers, as an alternative to electronic repeaters, is that they make it possible to upgrade the information-carrying capacity of a system by simply increasing the data rate and/or the number of optical channels.