Optical and electrical characteristics of pulsating 1.3 µm InGaAsP double heterostructure lasers

Self sustained pulsations, superlinear emission and negative resistance behavior of several 1.3 µm InGaAsP stripe geometry DH lasers are studied as a function of temperature and drive current. The pulsations are observed in a certain current range above threshold. This current range increases with increasing temperature. Also the maximum modulation increases with increasing temperature. The differential quantum efficiency in the region of superlinear emission was found to increase with increasing temperature and the magnitude of negative resistance decreased with increasing temperature. Time resolved measurements of the near field shows that a self-focussing of the optical beam occurs during the emission of the pulse. These phenomenon are predominently observed in nitride-stripe lasers.