High stability double-pass backward Er-doped superfluorescent fiber source incorporating an Er-doped fiber filter

An Er-doped fiber (EDF) filter was used in a double-pass backward Er-doped superfluorescent fiber source (SFS) to improve its mean wavelength thermal stability. The thermal stabilities of mean wavelength for four configurations of SFS with or without the Er-doped fiber filter and Faraday rotator mirror were explored experimentally. The result shows that with an EDF filter and a FRM incorporated in a double-pass backward Er-doped SFS, the mean wavelength variation can reach 32.02 ppm over the temperature range of -40 °C to 60 °C. The mean wavelength was around 1561 nm and its bandwidth reached 15.8 nm. The pump power was 55 mW at 974.2 nm and the output power reached 7.8 mW with 5-m Er-doped fiber.