Simple self-synchronization scheme for OTDM packet networks

Summary form only given. In this paper, a simple self-synchronization scheme employing only one SOA and optical filter based on the self-phase modulation (SPM) induced frequency chirping is proposed. When an incoming OTDM packet composed of short optical pulses is introduced into the SOA, the SOA gain is saturated abruptly by the first pulse, and then recovers slowly. If the bit period is much shorter than the carrier lifetime, the gain will only recover partly when the second pulse arrives and be saturated again. Therefore, only the first pulse experiences larger gain and phase variations. As phase change always accompanies frequency chirping, the first pulse acquires larger frequency shifting than other pulses do. Behind SOA, if we arrange an optical band-pass filter (OBF) whose center frequency corresponds to the frequency shift of the first pulse, the first pulse can be extracted out from the OTDM packet. Here EDFA is exploited to boost the power of the OTDM packet signal to the required level if necessary.