  The dependence of the relative population inversion in Er3+-doped fiber
amplifiers (EDFAs) upon temperature and cross sections, taking into account the
amplified spontaneous emission (ASE), are investigated theoretically by the
modified rate equation model for 980 nm and 1470 nm pumping conditions. For the
temperature range from 0 to +50 oC and at the different signal wavelengths, the
temperature and cross section dependent gain characteristics with respect to
pump powers are also examined in detail for the both conditions. As a
consequence, the dependence of the performance of EDFAs on temperature for 980
nm pumping is weaker than that for 1470 nm pumping, not only at room
temperature but also at the temperature range of 0 to +50 oC. However, the
performance of EDFAs is more efficient at the pumping wavelength of 1470 nm
than that of 980 nm for a wide range of temperature and high-pump powers. The
results of this theoretical model are a good agreement with the experimental
ones in the literature.
