All-optical gain clamping and flattening in L-Band EDFAs using lasing-controlled structure with FBG

In this study, we have theoretically and experimentally analyzed gain clamping and gain spectrum flattening performance in L-Band EDFAs based on a lasing-controlled structure using a symmetrical FBG couple at C-Band. Its performance was compared with a single-stage bidirectionally pumped conventional L-Band EDFA design. By optimizing the reflection (Bragg) wavelength of the FBG, a wide gain-clamped dynamic range (33 dB) and a wide gain-flattened spectrum (35 nm) were obtained at a maximum gain of 19.70 dB. Our results have shown that the experimental results are highly consistent with the theoretical and simulation results. Consequently, the proposed L-Band EDFA design using a lasing-controlled structure with FBGs can provide a wide gain clamped and gain flattened operation in the desired signal power levels.