All-optical regenerative NRZ-OOK-to-RZ-BPSK format conversion using silicon waveguides.

We propose a scheme to achieve regenerative format conversion from a distorted non-return-to-zero-on-off-keying (NRZ-OOK) signal to a return-to-zero-binary-phase-shift-keying (RZ-BPSK) signal of high quality in an integrated device. This proposal is achieved by employing an interferometer on a silicon chip with a coupled ring resonator optical waveguide embedded in one arm. In this scheme the amplified NRZ-OOK signal is injected into the converter together with a locally generated return-to-zero (RZ) pulse train at a different wavelength. Owing to the linear and nonlinear effects in the silicon waveguides, the RZ pulse train changes to a clean RZ-BPSK signal after it is cross modulated by the NRZ-OOK signal. To verify the feasibility of our scheme, we simulate the conversion at 10 Gbits/s.