Erbium-Doped Fiber Amplifier Review

This paper is describing and investigating four crucial areas of Erbium Doped Fiber Amplifier (EDFA). First is the atomic part, where it is meaningful to give deep and details information of erbium spectra structure and its energy level. The atomic spectrum is one crucial part in defining and understanding amplification phenomena. The second part based on understanding, investigating and analyzing of the theoretical background of EDFA where spontaneous and stimulated emissionsare the main targets of this portion. The third part is the EDFA design, where variety of investigationsillustrated viadifferent design of configurations from the single pass to the quadruple pass. Thepurpose of EDFA designsis to prove experimentally the high-gain and low-noise-figure utilizing novel methods and techniques. The fourth is the critical-review part, where many research papers reviewed to figure out their strengthsand weaknesses at different interpretation. The critical review is to describe and specifythe limitationsof the classical understanding of EDFA and to depict and conceive the next generation characteristics of the fiber laser and fiber amplifier.