Temperature-Dependent Performance Optimization of a Filtered ASE Source Employing Low-Concentration Erbium-Doped Fiber

Research on the thermal stability of amplified spontaneous emission (ASE) has mostly focused on broadband spectra. High-precision fiber optic gyroscopes (FOGs), however, require spectrally filtered sources. The impact of erbium-ion doping concentration on the temperature performance of such filtered sources remains relatively explored. This work systematically compares low-concentration and high-concentration erbium-doped fibers (EDFs). The fibers are used in a bidirectional forward-pumped ASE configuration. This configuration integrates a 1530 nm Gaussian filter isolator. The optimized low-concentration EDF fully absorbs pump power over a longer length. Its gain-profile temperature shift partly compensates the filter passband shift. At the optimum fiber length of 10 m, this source shows a mean wavelength temperature drift of only 0.107 ppm/°C. In contrast, the commercial high-concentration EDF gives a drift of 0.136 ppm/°C. The power conversion efficiency of this source reaches 26.9%. The commercial EDF attains 24.5%. The results demonstrate that reducing the Er3+ doping concentration simultaneously improves the wavelength thermal stability and efficiency of filtered ASE sources. This finding offers important guidance for high-accuracy FOG design.