A New Design and Fabrication of Tapered Fiber-Based Loop Mirror as a Gain Flattened Erbium Doped Fiber Amplifier

The purpose of this study is flattening the amplified spontaneous emission (ASE) spectrum based on an erbium-doped fiber (EDF) by using a standard fiber-based loop mirror (FLM) and tapered fiber. Subsequently, an over-coupled coupler is fabricated to realize the FLM, which is integrated to an EDF pumped by a 980-nm laser diode with a power level of 100 mW. By introducing an appropriate amount of bend-induced and inserting the optical tapered fiber in FLM, the ASE spectrum of the EDF was flattened within 0.9 dB over a wavelength range of 31 nm in the C-band (1525 nm-1556 nm).