Miniaturized MMZI concatenated FLM for gain equalization of ASE response of an EDFA

•A MMZI has been employed, for the first time, for gain equalization of ASE spectrum of an EDF.•The ASE of an EDF has been flattened over a range of 35nm in the C-band with an accuracy of ±0.46dB.•The stable spectrum of the MMZI over other all-fiber interferometers is the major advantage.