A novel all-optical clock recovery scheme

We experimentally demonstrate all-optical clock recovery (CR) from the nonreturn-to-zero (NRZ) data without any preprocess measure. Multi-quantum-well (MQW) Fabry-Pérot semiconductor optical amplifier (FP-SOA) plays the dual role of the data format converter and the clock recovery device. To achieve amplitude equalization of the recovered clock pulses, a self-nonlinear polarization switching (SNPS) including the FP-SOA itself, two polarization controllers (PCs) and a polarization beam splitter (PBS) is employed. Using the presented scheme, stable and low jitter 35.80 GHz optical clock pulses were directly extracted out from input NRZ data. This scheme has some distinct advantages such as being transparent to data format, free preprocess, free pre-amplification, convenient tuning, good tolerance to long “0s” data, and good tolerance to wavelength drifting of input data.