Direct modelling of error statistics for data transmission through a high data rate communication line using a four-level phase modulation format

This paper presents mathematical modelling results for information transmission by optical pulses through a fibre-optic communication line at a rate of 80 Gbit s^-1 per WDM channel using a four-level phase modulation format. We examine the influence of nonlinear effects on the profile of optical pulses propagating along the fibre. Using direct optical signal detection, we analyse error statistics and demonstrate an uneven error distribution over various symbol combinations.