H.J. Thiele

Reduction of intrachannel nonlinear distortion in 40-Gb/s-based WDM transmission over standard fiber

Intrachannel cross-phase modulation and four-wave mixing in high-bit-rate WDM transmission systems employing standard single-mode fiber are investigated. The effects of imperfect third-order dispersion compensation are included in the study and analytical expressions giving optimum values of dispersion precompensation minimizing the distortion due to the intrachannel nonlinear effects are derived.

Prediction of transmission penalties due to cross-phase modulation in WDM systems using a simplified technique

Cross-phase modulation (XPM) is a dominant impairment in WDM networks employing high bit-rates and narrow channel spacing. The optimization of future networks requires rapid and accurate techniques to predict XPM-induced penalties. We demonstrate the accuracy of predicting penalties from the distortion of a CW probe channel and show that as a consequence, XPM penalties can be calculated by a simplified numerical technique.

Investigation of XPM distortion in transmission installed fiber

The impact of cross-phase modulation (XPM) on WDM transmission was investigated for different bit rates up to 10 Gb/s/sup -1/ in a field experiment over the installed LEANET/UK fiber network and compared with laboratory experiments. Effects of interference between XPM components generated in concatenated fiber spans are reported.

Optimisation of WDM transmission of multi-10 Gbit/s, 50 GHz-spaced channels over standard fibre

Transmission of 4/spl times/10 Gbit/s, with very narrow channel spacing (50 GHz) over landline distances of up to 800 km of standard fibre is reported using a single-span, dispersion-managed recirculating loop. An improved dispersion compensation scheme allowing to minimise nonlinearity-induced distortion is described.

Influence of fibre dispersion on XPM pulse distortion in WDM systems

Pump-probe experiments used to study cross-phase modulation (XPM) induced amplitude distortion in fibre systems using dense WDM are described. New experimental and computer simulation results show the dependence of XPM on dispersion map, channel spacing and bit-rate.

Cross-Phase Modulation Distortion in Multi-Span Dense WDM Systems

The intensity distortion caused by cross-phase modulation (XPM) limits transmission distances and capacities of high-speed, dense WDM systems. Optimisation of system design can minimise the impact of XPM. Pump-probe experiments are described investigating XPM distortion as a function of typical system parameters for a single fibre link and for multi-span transmission using a fibre recirculating loop. Different dispersion maps and their influence on the XPM generation and phase-to-intensity conversion were investigated. The results are in good agreement with theory and computer simulations. The distortion depends strongly on channel walk-off in the system, increasing for narrow channel spacing and low dispersion.

Optimisation of the Dispersion Map of Compensated Standard-Fibre WDM Systems to Minimise Distortion due to Fibre Nonlinearity

Nonlinear fibre effects such as self- and cross-phase modulation combined with the group velocity dispersion result in intensity distortion of the propagating signals in WDM links, limiting the maximum transmission distance. The transmission distances can be increased by optimising the dispersion map to reduce the impact of nonlinearities. In this paper, we report the results of recirculating fibre loop experiments and computer simulations investigating the use of undercompensation to minimise the nonlinear distortion in multi-span compensated standard-fibre links.