Impact of the gain saturation on steady states of bit optical pulses in an erbium-doped single-mode fiber amplifier

Steady ultrashort bit pulses, originating in single-mode erbium-doped fiber amplifiers, are analytically investigated. This type of steady bit carriers can be grown in real time scale due to resculpturing external optical pulses incoherently by fiber amplifier in the traveling-wave regime. The analysis performed is related to the regimes without and with the gain saturation in a doped fiber and demonstrates that single-mode fiber amplifiers can form and support in these regimes steady bit pulses in the form of bright solitons. For both the regimes, the amplitude and frequency distributions are estimated, and the impact of the gain saturation is revealed.