Abstract

Whenever an optical signal is tuned into a resonance such as a band pass filter or a laser transition, a dispersion arising from the resonance starts playing a role on the propagation of the signal. The effect of the dispersion on the signal depends on few parameters such as the dispersion spectral width, the amplitude or the strength of the interaction of the signal with the resonance. In long haul optical telecommunication systems, a certain number of optical ampifiers are required to restore the depletion of the optical, signal caused by the filer losses. Neverthless the effect of the resonant group velocity dispersion (GVD) provided by the amplifiers plays a minor role as long as non zero GVD for the link is chosen. More critical is the effect of the resonant GVD in erbium doped fiber lasers (EDFL's) where the length of the active medium may, in principle, coincide with the the length of the cavity. The effect of a spectrally varying GVD profile is that of distorting the temporal profile of a pulse during the propagation [1]. In the soliton fiber lasers the temporal asymmetry provided by the resonant dispersion is partially compensated by the restoration of the nonlinear gain, and eventually the ultimate pulse duration differs from the natural limit imposed by the gain bandwidth.

© 1993 Optical Society of America