Effect of self-phase modulation on a dispersion compensated link employing a dispersion-compensating fiber

Abstract

A study of the effect of self phase modulation (SPM) on a fiber link consisting of a non-dispersion shifted fiber (NDSF) and a dispersion compensating fiber (DCF) operating at 1550 nm has been carried out. The characteristics of signal pulse transmission through the fiber combination of NDSF followed by DCF (post-compensation) and DCF followed by NDSF (pre-compensation) are obtained by numerical simulation. It is found that though in the linear regime there can be exact compensation of dispersion for either combinations of NDSF + DCF and DCF + NDSF, in the nonlinear regime of transmission the two combinations behave very differently. For the case of NDSF + DCF the pulse width increases and attains a maximum value before decreasing with the input signal power, whereas for the combination of DCF + NDSF the pulse undergoes compression. It is also shown that when the linear dispersion in NDSF is slightly under compensated by DCF, the pulse width in the DCF + NDSF combination does not change appreciably for a large range of input signal power.