The homogeneous, two-level approximation of amplification in erbium-doped fibers is the basis for many amplifier models. Even three- or four-level models might be handled with modi- fied propagation equations in the two-level model i. The homogeneous, two-level approximation of amplification in erbium-doped fibers is the basis for many amplifier models. Even three- or four-level models might be handled with modi- fied propagation equations in the two-level model if the popu- lation densities in other levels are small. For example, in pump excited-state absorption (ESA), most of. C. Randy Giles, Member, IEEE, and Emmanuel Desurvire, Member, IEEEWhile all the models discussed to this point have been for steady-state operating conditions, many applications use the er- bium amplifier to amplify time-varying signals. It is well-known that the long metastable lifetime and the energy-storage prop- erties of the gain medium act to smooth out fluctuations in the amplifier's operating point, leadi. pk auk The overlap integral rk, is calculated to be.
[PDF Version]