1 Application of the Saddle Point Method for the Evaluation of Crosstalk Implications in an Arrayed Waveguide Grating Interconnection Thomas Kamalakis and Thomas Sphicopoulos 1 Abstract: The effect of in-band crosstalk can pose severe limitations in an optical network. In this paper, the implications of in-band crosstalk induced by an arrayed waveguide grating router, in a passive NxN optical interconnection, are analyzed with non Gaussian statistics using a numerical model. The model is based on the saddle point approximation and takes into account the fluctuations of the transfer function’s sidelobes induced by the phase errors in the grating arms, phase noise, polarization variations, bit misalignment, shot and thermal noise. The influence of the above effects on the interconnection’s BER is analyzed. The validity of the Gaussian assumption for the crosstalk noise statistics is discussed. Finally, the model is used to examine the mean crosstalk requirements for various numbers of network nodes. Index Terms: Phased Arrays, Optical crosstalk, Gratings, Wavelength division multiplexing. 1 The authors are with the Department of Informatics and Telecommunications of the University of Athens, Panepistimiopolis, GR-157 84, Athens, Greece. Thomas Kamalakis: Telephone: (+3021) 07275335, e-mail address: thkam@di.uoa.gr, Fax: (+3021) 07275601. Thomas Sphicopoulos: Telephone: (+3021) 07275313, e-mail address: tsfikop@di.uoa.gr, Fax: (+3021) 07275601.