Experimental analysis of SOA-based 2R and 3R optical regeneration for future WDM networks

Summary form only given. The large scale deployment of all-optical wavelength-division multiplexing (WDM) networks will require signal regeneration due to signal impairments occurring in transmission spans and optical switching nodes/cross-connects. A 2R regenerative interface for non-return to zero (NRZ) signals based on semiconductor optical amplifiers (SOAs) has been proposed by Chiaroni et al. (1997), with clear demonstration of regenerative properties in the amplitude domain. In this paper, a 3R regenerative interface based on the same core structure is described. The core of these interfaces is composed of the association of a wavelength converter (WC) under cross-gain modulation (XGM-WC) and a wavelength converter under cross-phase modulation (XPM-WC), both operating in polarity-inverting mode. Basically, the role of the first WC is to convert power fluctuations into extinction ratio variations and to provide the second WC with a constant input power. The second converter is in turn mainly used to regenerate the extinction ratio thanks to its nonlinear transfer function. This interface in addition limits the accumulation of amplified spontaneous emission (ASE) noise.