A triggerable semiconductor laser emits light in very short (0.1 ns) intense (0.1 W) pulses with a few nanosecond periods when biased a fraction of a milliampere above a threshold current. Single uniform lightwave pulses can be triggered by fractional milliampere current pulses up to several nanoseconds in duration. This behavior was first seen in computer simulations of devices with a high electron-trap density (other causes are possible). Devices exhibiting this behavior have been found among the population of AlGaAs stripe lasers made by deep proton bombardment. A simple lightwave pulse regenerator has been built by adding a photodiode with less than unity gain. This circuit emits lightwave pulses with 6 pJ energy, less than 0.2 ns in duration, and with an amplitude that is up to 15 times larger than the input pulse.