Investigation of all-optical nonreturn-to-zero-to-return-to-zero format converter based on a semiconductor optical...

A simple and robust all-optical nonreturn-to-zero to return-to-zero (RZ) format converter is demonstrated and investigated using a semiconductor optical amplifier (SOA) and a reconfigurable delayed interferometer. The scheme can be used to convert input signals at different bit rates and obtain converted signals with tunable duty cycles. Format conversion at 10 Gb/s is achieved with a negative power penalty of -4.9 dB at a bit-error rate of 10(-9). Transmission of the converted RZ signal over a dispersion-managed fiber link of 80 km results in only a small power penalty of 0.9 dB. In addition, the format converter is found to be insensitive to the power fluctuation of the optical clock, as the SOA works in the saturation regime.