Line narrowing and spectral hole burning in single-mode Nd^3+-fiber lasers

Line narrowing in the output spectrum of a Nd-doped silica-fiber laser with spectrally flat reflectors is interpreted to indicate a substantial homogeneous contribution to the 1.09-microm fluorescent linewidth. By using a fiber Bragg reflector, frequency-stable operation with 100-GHz bandwidth is obtained, dominated by power broadening and spectral hole burning.