Flat spectrum superfluorescent erbium fiber source based on a Fresnel reflector

A superfluorescent Erbium-doped fiber source (SEFS) in double-pass forward configuration incorporating a 90° cleave angle at 1550nm input-port of wave-division multiplexer (WDM) that acts as a Fresnel reflector, is presented. The output characteristics of the proposed configuration are analyzed. The experimental results of 90° cleave angle, no-reflector (8° cleave angle), and fiber loop mirror schemes are compared. It is demonstrated that the output characteristics can further be enhanced by employing a gain flattening filter (GFF) in the proposed scheme. A power of 10.68 mW, mean wavelength 1548.20 nm, bandwidth 37.94 nm, and level of flatness ≤ 2.81 dB are obtained with the improved design.