Parallel WDM Signal Processing in Mixed NRZ and RZ Transmission Networks Using a Single Optical Gate With Multiple Switching Windows

We propose and demonstrate in experiment a multiple switching-window optical gate (MW-OG) for applications on parallel multiwavelength processing. The proposed scheme is a multiwavelength compatible version of the conventional Sagnac interferometric switch that offers independent controllability of switching windows at different wavelengths. This feature makes possible the data format conversion from nonreturn-to-zero (NRZ) and return-to-zero (RZ) with parallel pulsewidth tunability for wavelength-division-multiplexed signals. It also leads to the multiwavelength regeneration against chromatic dispersion and amplified spontaneous emission noise for both NRZ and RZ signals over the optical sampling processes. The MW-OG is then used as inline signal regeneration in a mixed NRZ and RZ data format transmission network over standard single-mode fiber without dispersion compensation. The regeneration is carried out at a central node that works as a terminal and an intermediate for various interconnections among nodes. Transmission performances are significantly improved for all channels simultaneously by parallel pulsewidth management in accordance with their modulation formats and lightpaths.