Spectral gain hole-burning was observed at low temperatures in an erbium-doped fiber amplifier with GeO2:SiO2 core. At the peak wavelength lambda = 1.535 mu-m, homogeneous linewidths determined from the observed hole widths have a power law dependence on temperature DELTA-lambda-(hom)-proportional-T1.61. At room temperature, the extrapolated homogeneous linewidth is 4 nm and the inhomogeneous linewidth is 8 nm.