4 Crosstalk in WDM optical networks Authors: M. AvattaneoO, E. Iannone*, R. Sabellao ° Ericsson Telecomunicazioni, Research & Development Division, Rome, Italy * Fondazione Ugo Bordoni, Rome, Italy Reference e-mail: sabella@RD.teLericsson.se Abstract The impact of linear and non linear crosstalk on the transmission performances of multi-wavelength optical transport networks is analysed. A performance evaluation of some relevant geographical networks is also reported. I·INTRODUCTION The transmission capacity and the network nodes throughput are expected to increase more and more, due to the increasing demand for new services, towards the advent of broadband communications. The optical technology provides the possibility of significantly increase the transmission capacity and, by the use of wavelength division multiplexing technique, also allows switching and routing functions to be accomplished directly in the optical domain, without the need to convert the high speed signals in electrical format. The possibility of achieving such function quite independently of the transmission format and the signal speed, provide the network the property of transparency, which is a significant feature for building flexible networks. Different demonstrators and field trials have been realised [1,2]. In such experiments, it has been evidenced that the crosstalk, besides the node losses and the amplified spontaneous emission (ASE) noise due to optical amplifiers, represents the main limitation for the transmission performance of the network. The aim of this work is to analyse the limitations imposed by crosstalk to the performances of the WDM optical transport network layer. Optical Network Design and Modelling H. van As & A. Jukan (Eds.) © 1998 IFIP. Published by Chapman & Hall