Optical Fiber Amplifiers-Review

Abstract

This paper reviews optical fiber amplifiers such asErbium doped fiber amplifiers EDFAs, many types of Ramanamplifiers RAs, Thulium doped fiber amplifiers, Tellurite-basedfiber Raman amplifiers, semiconductor optical amplifiers andfiber optic parametric amplifiers, principle of operation andconstruction. As these amplifiers are used for optical fibercommunication projects so we shall go through their maincharacteristics which are amplifier gain and span length,wavelength bandwidth and noise. Current repeater spacing andspeed of EDFA is in the range of 80-100 Km and 40 Gb/s whilethose for RA is in the range of 100-160 Km and 160-320 Gb/s.Each type of amplifier is suitable for certain applicationdepending on these characteristics. In metro/access networksthere are many add/drop locations resulting in high loss, coarsewavelength division multiplexing with about 20 nm separationbetween each channel as with this principle cheap multiplexingand laser transmitters are used.