BIT CORRELATION AND MEMORY EFFECTS IN HIGH-SPEED PUMP MODULATION OF AFIBER LASER

In the context of optical communications, we study experimentally the behavior of a pump-modulated fiber laser at frequencies close to the r elaxation oscillation frequency. We show that correlations can appear between successive ''1'' bits in various situations. This ''memory eff ect'' can be interpreted using a simple deterministic model, and we sh ow that this effect is related to the behavior of the population inver sion, which does not follow adiabatically the photon number. Our resul ts also suggest the existence of an optimum pump bias value for optica l communications, slightly below threshold.