All-optical clock extraction of NRZ data using semiconductor optical amplifiers

Summary form only given. In current lightwave communication system, non-return-to-zero (NRZ) formatted data is preferred because of its bandwidth efficiency and better error performance. Unlike RZ data, the NRZ data doesn´t contain a clock component in its modulation spectrum. Thus a necessary step in all-optical clock recovery from NRZ data is to extract the clock component. Recently, all-optical clock recovery from NRZ data using SOA was demonstrated. When NRZ data pass through a SOA, an overshoot at each leading edge is generated due to gain saturation of SOA. These overshoots have rich clock component. In this paper, extraction of clock component using SOA is studied both experimentally and theoretically.