An improved chromatic dispersion compensation technique employing an optical all pass filter equaliser in a 10 Gb/s optical system

The chromatic dispersion (CD) of a single mode fibre (SMF) is an important issue in a long haul optical communication system when the new generation of optical system is introduced operating at the wavelength of 1.55 μm with the bit rate of 10 Gb/s. The CD effect will result in pulse spreading and causes inter-symbol interference (ISI). This paper proposes a promising technique to compensate CD by using an optical all pass filter (OAPF) as an equaliser. The phase response of OAPF will be designed to equalise the phase delay of SMF which is the main cause of CD. The simulation of the mathematical model of the optical system at 10 Gb/s employing the proposed OAPF will be presented. A minimum mean square error technique was used to optimise the equaliser and the simulation results show the pulse spread improvement of 33% and fully compensated were achieved at full-width half-maximum (FWHM) for 100 and 160 km of SMF. respectively. The eye diagram also shows an improvement of 32 dB in dispersion penalty when OAPF equaliser is used at a distance of 160 km.