Performance of cascaded wavelength converters

We present a theoretical investigation of performance of systems employing cascaded wavelength converters. We consider a path consisting of up to 21 stages of wavelength conversion, in which arrayed-waveguide grating multiplexers are used for optical multiplexing, demultiplexing and filtering. Our system model includes the ASE noise accumulation within each stage, and the excess ASE noise and residual signal power which accumulate due to imperfect filtering in realistic devices. We calculate the impact of these factors on the signal quality, as measured by the Q-factor and bit-error rate performance, and demonstrate that ER degradation alone may not be the ultimate limiting factor in the cascadability of XGM-WCs.