Multi-Wavelength All-Optical Regeneration

Progress in Multichannel All-Optical Regeneration Based on Fiber Technology

“…Finally, in a third approach, which has been developed for WDM OOK signals, carefully engineered dispersive walkthrough maps in fibers are used to avoid the inter-channel crosstalk [30,[33][34][35][36][37][38][39][40][41][42][43][44][45][46][47][48]. In these schemes a high local average dispersion value ensures that the nonlinear inter-channel effects are significantly weaker due to the fast walk-off time among the various WDM channels, while a low overall average dispersion value ensures that the nonlinear effect used for the regeneration process itself (SPM) is sufficiently retained, Fig.1 (c).…”

“…It is, though, worth pointing out that, to date, SPM-based regenerators are the most promising ones due to their simple implementation and excellent performance and thus the easiest to be adapted for multi-wavelength operation if OOK signals are used. These types of SPM-based regenerators differ in their architectures, according to whether the various WDM channels all propagate in the same direction [30,[33][34][35][36][37][38][39][40][41] or some in opposite directions [42][43][44][45][46][47][48] within the nonlinear fiber, see Fig. 1 (c.i-v).…”

“…1 (c.i-v). This can either be through a carefully tailored highly nonlinear fiber (HNLF) [41][42][43][44][45][46][47][48], a dispersion decreasing fiber (DDF) [33] or chromatic dispersion-managed fiber assemblies [30,[34][35][36][37][38][39][40]. Decision-threshold based filtering at the regenerator output may then be performed in a variety of different ways, namely the filter may be centered at the same wavelength as the original signal (usually referred to as a spectrally filtered optical soliton regenerator) [40] , see Fig The all-optical multichannel limiters that use spectrally filtered optical solitons rely on progressive pulse reshaping of the incoming signal during propagation in an anomalous HNLF at a precise input power (see Fig.1 (c.i)).…”

“…dispersion compensating fiber (DCF)) followed by a periodic group delay device (PGDD) with a saw-tooth-like profile, which acted as a channelized dispersion compensator [34][35][37][38]. This configuration allowed the channels to uni-directionally walk through each other, reducing any bit-pattern dependence of the nonlinear crosstalk.…”

Phase Regeneration of QPSK Signal in SOA Using Single-Stage, Wavelength Converting PSA

“…However, this approach is often marred by the difficulty in isolating the regenerated channels from each other during processing [1], [2], which either requires complicated optical schemes, or presents difficult engineering challenges, such as dispersion management in highly nonlinear fibre (HNLF). Processing multiple signals individually, each in their own spatially separated nonlinear medium, is perhaps a straight-forward alternative, even though it might not carry all of the scaling benefits that are often associated with all-optical signal processing.…”