High-Stability Er-Doped Superfluorescent Fiber Source Incorporating Photonic Bandgap Fiber

A tunable photonic bandgap fiber filter was incorporated in an Er-doped superfluorescent fiber source to improve its mean wavelength thermal stability. This simple filter was able to successfully compensate the mean wavelength to less than 10 ppm from - 40°C to 70°C. When the environmental temperature was controlled to ±0.5°C, the superfluorescent fiber source (SFS) exhibited a long-term mean wavelength stability of ±1 ppm over 11 h. With 60-mW pump power at 974.2 nm, an optimal Er-doped fiber length of 8 m was found, and the final output power of the compensated SFS reached 8 mW.