MODELING ERBIUM-DOPED FIBER AMPLIFIERS

Erbium-doped fiber amplifiers are modeled using the propagation and rate equations of a homogeneous, two-level laser medium. Numerical methods are used to analyze the effects of optical modes and erbium confinement on amplifier performance, and to calculate both the gain and ASE spectra. Fibers with confined erbium doping are completely characterized from easily measured parameters the ratio of the linear ion density to fluorescene lifetime, and the absorption of gain spectra. Then analytical techniques allow accurate evaluation of gain, saturation, and noise in low-gain amplifers (G less-than-or-equal to 20 dB).