Gain Flattening of Three-stage Erbium-doped Fiber Amplifier Based on GFF+VOA

A three-stage erbium-doped fiber amplifier (EDFA) based on a Gain flattening filter (GFF) and Variable optical observer (VOA) was developed. By studying the characteristics of GFF and VOA, pump power ratio, erbium fiber (EDF) temperature, and other factors, the extended C band (1527−1569 nm) with high gain, low noise, and gain flattening control was realized. In the experiment, a three-level optical path structure was used with the first and second stages using a bypass structure. The input optical signal power was -8 dBm, the gain tilt was -1, and the pump power ratio was 1.6. When the erbium fiber temperature was controlled at 55°, the amplifier recorded a gain of 19 dB, a maximum noise of 5.2 dB, and a gain flatness of 1.06 dB. The developed EDFA provided gain flattening in erbium-doped fiber amplifiers.