Analysis of absorptive bistable characteristics of multisegment lasers

The paper presents a new model of the static I-L characteristics of inhomogeneously pumped laser devices, such as SLEDs and multisegment lasers. These devices are known to exhibit hysteresis, and the paper considers both electrically triggered switching of multisegment lasers and optically triggered switching of SLED-like devices. Features of the model are; the inclusion of the wavelength dependence of the stimulated gain and the spontaneous emission characteristics, and the variation of the carrier density and photon flux in the longitudinal direction of the laser. The paper shows how the topology of the device, namely the relative lengths of the pumped and passive segments of the device, affect its threshold current and hysteresis. The effect on the threshold current and hysteresis of the injection of small currents into the triggering electrode of a split-stripe laser is also shown. It is seen that there are limits on both the relative length of the passive segment and also on the value of current extracted from the trigger electrodes if maximum hysteresis is to be achieved. The effect of the wavelength of externally injected light on its ability to initiate switching is also considered.