Time substructure of picosecond pulses emitted by heterolasers with spatially inhomogeneous injection

A high-resolution image-converter camera was used to record picosecond radiation pulses generated as a result of direct modulation of the current reaching heterolasers with isolated injection regions. Regular pulsations of the intensity with a period corresponding to the time of complete or half trip through the internal resonator, resembled those reported for similar lasers with mode locking in the external resonator.