A New Method of Gain-Flattening Filter for ASE Source Based Tapered Fiber Sagnac

Erbium-doped fiber amplifiers (EDFAs) Have played a key role in long distance WDM transmission systems, But the problem of this component is un-uniform gain spectrum in operational wavelengths at C communication window. The purpose of this study is design and feasibility new method of the amplified spontaneous emission (ASE) spectrum based on an erbium-doped fiber (EDF) gain flattening filter, by using a standard fiber-based Sagnac and tapered fiber. In the field of flattening process, fabrication tapered fiber on SMF-28 optical fiber as a different method. By introducing an appropriate amount of bend-induced and inserting the optical tapered fiber in Sagnac, the ASE spectrum of the EDF could be flattened on 20 nm range within 0.9 dB ripple over a wavelength range of 31 nm in the C-band.