  We have addressed the characteristic distinguishability of coherent states in
the temporal domain from a directly modulated quantum well-based gain-switched
laser diode. Using small-signal and large-signal models, we identify tunable
parameters to generate indistinguishable coherent states from an electrically
pumped semiconductor laser. The experiment confirms the generation of
indistinguishable signal and decoy coherent states as predicted by the
numerical simulation.
