The transmission performance in WDM-systems is different for the individual WDM channels. We investigated systematically this variation and wavelength dependence by using semi-analytical simulations. The benefit of this behavior in transparent optical networks is discussed and demonstrated in network case studies.
An overview of a wide choice of current technologies and components suitable for the use of 160 Gbit/s optical time domain multiplexing (OTDM) systems is given. A selection of the presented components were used to implement a 160 Gbit/s network. In a field trial on BT’s network we demonstrated transmission over 550 km and a fully operating OTDM network including a time domain add-drop multiplexer (TD-OADM) at a data rate of 160 Gbit/s at a single wavelength and a tributary data rate of 10 Gbit/s.
For 10 Gb/s and 40 Gb/s NRZ signals the maximum reach of a WDM transmission system depends on the optimization of the inline dispersion scheme, which is different for both data rates for SPM limited transmission systems. Therefore, a mixture of both data rates in the same fiber may cause an impairment of the system performance. This can be reduced introducing additional pre-compensation. The value for the optimum precompensation varies with the inline dispersion scheme and the launch power. A design rule to determine the optimum pre-compensation was derived empirically for SSMF and NZDSF. For fixed inline dispersion compensation on SSMF, the maximum reduction of the system reach without pre-compensation is found to be up to 6 dB, compared to optimized inline dispersion compensation schemes. By applying optimal pre-compensation this impairment can be reduced to less than 1 dB. For NZDSF with pre-compensation the system performance can also be improved significantly. Thus WDM systems using different line rates at the individual wavelengths are possible with only a small penalty.