Abstract
The optical feedback dynamics of two multimode InAs/GaAs quantum dot lasers emitting exclusively on sole ground or excited lasing states is investigated under the short delay configuration. Although the two lasers are made from the same active medium, their responses to the external perturbation are found not much alike. By varying the feedback parameters, various periodic and chaotic oscillatory states are unveiled. The ground state laser is found to be much more resistant to optical feedback, benefitting from its strong relaxation oscillation damping. In contrast, the excited state laser can easily be driven into very complex dynamics. While the ground state laser is of importance for the development of isolator-free transmitters, the excited one is essential for applications taking advantages of chaos such as chaos lidar, chaos radar, and random number generation.