The design and implementation of a software based gain control for EDFAs used in long-haul optical networks

Abstract

The optical gain spectra of erbium-doped fiber amplifiers (EDFAs) have a nonlinear structure in the C-band region. Therefore, when the optical amplifier chain is used, in other words, when successive amplifications are made, the gain values obtained at some wavelengths will differ. As a consequence, some wavelengths will be reduced and will disappear before reaching the receiver side in long-haul optical networks. To overcome this, it is attempted to bring the gain values to the same level for all wavelengths used. Electronically, the dynamic gain value is achieved by controlling the power of the pump laser. Pump lasers are controlled based on two parameters consisting of current and temperature. In this study, an EDFA operating in the C-band region was designed, and an electronic board that would control the gain of this EDFA and software to control it via computer were implemented. In conclusion, an automatic control of the gain of the EDFA operating in the C-band region was achieved, and gain ripple values in the range of 0.17–0.30 dB were obtained.