A theoretical analysis of optical clock extraction using a self-pulsating laser diode

The potential for using inexpensive compact disc laser diodes as optical cl ock extraction elements in transparent networks has led to an increase in r esearch into the dynamics of self-pulsating laser diodes. We use a rate-equ ation model to simulate the synchronization of the self-pulsating laser out put pulses to a periodic optical signal. In particular, we investigate the time it takes for the laser to synchronize to the input signal and also, th e time taken for the laser to unlock when the signal is removed. The effect of varying the power of the optical signal and the detuning of the input s ignal frequency relative to the laser's self-pulsation frequency are determ ined. Our results enable us to identify important issues which need to be a ddressed when a self-pulsating laser diode is used in a clock extraction su bsystem. In particular, we find that the signal frequency and laser free-ru nning frequency must be as close as possible to minimize errors. Also, the higher the signal power the quicker the laser synchronizes to the signal, a lthough we find that if the power becomes too large the laser can no longer lock, which would cause a significant increase in detection errors.