Optical regenerative NRZ to RZ format conversion based on cascaded lithium niobate modulators

Optical regenerative nonreturn-to-zero (NRZ) to return-to-zero (RZ) format conversion using a lithium niobate phase modulator and a lithium niobate intensity modulator is proposed and demonstrated. The key advantage of the proposed format converter is that the converted RZ signal has a very small pulse width, which can be multiplexed to a higher bit rate using optical time division multiplexing technology. The operation can greatly reduce the timing jitter of the degraded NRZ signal due to the regenerative property of the proposed scheme. Besides, the format converter can also support multi-channel operation. An experiment is performed with the feasibility of the scheme demonstrated.