A new scheme for novel all-optical wavelength conversion with ultrabroad conversion tunability and modulation-transparency

A scheme named “spoof” four wave mixing (SFWM) is proposed, where a dynamic refractive index grating induced by the beating of the co-propagating pump and signal is able to modulate a Bragg grating (BG) to create additional reflective peaks (ARPs) at either side of the unperturbed BG bandgap. When a probe wave located at the wavelength of ARPs is counter-propagating, it is reflected from the induced ARPS while tracking the signal data information but at the new wavelength. In contrast to the well-known FWM, where the induced dynamic refractive index grating modulates photons to create a wave at a new frequency, the SFWM is different in that the dynamic refractive index grating is generated in a nonlinear BG to excite ARPS at either side of the original BG bandgap in reflection spectrum. This fundamental difference enable the SFWM to avoid the intrinsic shortcoming of stringent phase matching required in the conventional FWM, and allows novel all-optical wavelength conversion with modulation format transparency and ultrabroad conversion range, which represents a major advantage for next generation of all-optical networks.