All-optical clock recovery from 2.5 Gbit/s NRZ data using selfpulsating 1.58 mu m laser diode

For the first time, all-optical clock extraction from 2.5 Gbit/s NRZ data is demonstrated using a two contact InGaAsP semiconductor selfpulsating laser diode (SP-LD) for what the authors believe to be the first time. The saturable absorber region of the device was doped with Zn ions to reduce the carrier lifetime such that strong selfpulsations at frequencies up to 4GHz were obtained. Injection of a 10μW optical data singal at a wavelength ∼ 15 nm lower than the lasing wave-length was sufficient to synchronise the selfpulsations to the incoming NRZ data stream. Similar effects were seen for RZ foramted data. Such all-optical clock extraction tehcniques will find application in future multigigabit per second optical networks and for OEIC applications.