Abstract

A skillful means of circulating loop experiments using Er-doped fiber amplifiers (EDFAs) has exhibited the feasibility of ultralong-distance transmission in optical amplifier systems for both a non-retum-to- zero (NRZ) signal^1,2 and a soliton signal.³ The simplicity of the IM-DD system is advantageous regarding modulation and demodulation, but the limitation from the fiber chromatic dispersion is expected to be much more serious compared to the coherent and the soliton systems which can compensate the dispersion by delay line equalizing in the intermediate frequency and by fiber nonlinearity, respectively. In this paper, we investigate the limitation of the dispersion for an IM-DD ultralong-distance system using an electroabsorption (EA) modulator by a circulating loop.

© 1992 Optical Society of America