A study of pulsations, superlinear emission, and negative resistance in 1.3 µm InGaAsP double-heterostructure lasers

Self-sustained pulsations, superlinear emission, and negative-resistance behavior of several 1.3μm InGaAsP stripe-geometry double-heterostrueture 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, in general, increases with increasing temperature. All devices exhibiting superlinear emission were found to pulsate. The external differential quantum efficiency in the region of superlinear emission was found to increase with increasing temperature and the magnitude of the negative resistance decreased with increasing temperature. These phenomenon are predominantly observed in nitride-stripe or oxide-stripe lasers. Superlinear emission and negative-resistance behavior have not been observed in buried-waveguide lasers. The behavior of InGaAsP nitride-defined stripe lasers is found to be similar to that previously reported for proton-bombarded AlGaAs lasers.