Evaluation of chromatic dispersion in erbium-doped fibers

Transoceanic fiber optic systems that use erbium doped fiber amplifiers(EDFAs) require careful tailoring of chromatic dispersion along the length of the span. One of the parameters of interest to system designers is the additional chromatic dispersion introduced by the erbium ions in the EDFA. The effect of resonant chromatic dispersion due to erbium is also evident in the performance of short length fiber devices such as soliton lasers. Several methods have been used in the past to measure erbium-induced chromatic dispersion. Specifically, Fourier transform spectroscopy and the use of complex atomic susceptibility have been successfully demonstrated. In this paper, we evaluate the complex atomic susceptibility of these fibers with different dopant levels and derive the total dispersion (waveguide and material) of these fibers as a function of wavelength in the 1550 nm range