All-optical modulation-transparent wavelength multicasting in a highly nonlinear fiber Sagnac loop mirror.

An all-optical wavelength multicasting scheme using four-wave mixing (FWM) in a highly nonlinear fiber (HNLF) Sagnac loop mirror has been demonstrated. This proposed scheme has the advantage that even when the wavelength of a multicast channel overlaps with the pump-pump generated idler, clear eye diagram can still be observed. Six and ten 10-Gb/s multicast channels, compliant with the ITU grid, are successfully obtained by using two- and three-pump lasers, respectively. Multicasting of on-off shift keying (OOK) and differential phase-shift keying (DPSK) signals are both successfully demonstrated. The maximum power penalty of the multicast channels is less than 3.5 dB. Furthermore, compared with the non-loop configuration, up to 1.2 dB power penalty improvement can be achieved in this proposed Sagnac loop configuration. (c) 2010 Optical Society of America