Carrier-suppressed return-to-zero to non-return-to-zero format conversion based on a single fiber Bragg grating with knife-shaped spectra

We propose a novel carrier-suppressed return-to-zero (CSRZ) to non-return-to-zero (NRZ) conversion scheme based on a single custom-designed fiber Bragg grating (FBG) with a knife-shaped spectrum. The structure of the FBG is designed and synthesized using a discrete layer-peeling inverse scattering technique. It is shown that such an FBG can replace the combination of interferometer and the cascaded filter that is invariably employed in the reported schemes for CSRZ to NRZ format conversion. Simulation results show that conversion of 40 Gbit/s CSRZ into NRZ signals results in a Q factor that is 4.5 dB greater than the previously reported schemes.