The optical gain control of the erbium doped fiber amplifiers


Thesis Type: Postgraduate

Institution Of The Thesis: Gazi Üniversitesi, Fen Bilimleri Enstitüsü, Turkey

Approval Date: 2014

Student: GÖKHAN YENİLMEZ

Supervisor: MURAT YÜCEL

Abstract:

The optical amplifiers are very important in the ultra long haul fiber optical communication systems. Erbium doped fiber amplifier (EDFA) is the most widely used type in optical amplifier. In consequence of the rapidly increasing capacity needs in these systems, not only high gain but also flat gain characteristics are very important. However, gain spectrum of the EDFA is not flat. This property affects the output signal gain levels and some signal channels lost in the ultra long haul communication systems. For this reason, signal gain must be flattened in the EDFA. In this thesis, the output gain of EDFA is flattened with optical gain control method to eliminate these disadvantages of EDFA. For this purpose, three C band EDFA and two L band EDFA configurations are simulated in the OptiSystem 12.0 optical software and gain spectrum of the EDFA is optimized. The effects of the fiber Bragg grating (FBG), gain flattening filter (GFF), two stage system, optical feedback loop, and amplified spontaneous emission (ASE) reflection technique are analyzed in these configurations. After, all configurations are compared and determined the advantages and the disadvantages of these configurations.