A short-period, strained superlattice structure includes two coupled quantum well layers separated by a barrier layer. The quantum well layers are preferably formed of indium arsenide and are 2 monolayers thick. The barrier layer is preferably formed of gallium arsenide and is 2 to 10 monolayers thick. The quantum well layers have a lattice parameter or constant which is sufficiently different from that of the barrier layer that a permanent strain exists in the surface. The layers are sufficiently thin that they remain in an unrelaxed state, thereby precluding the formation of misfit dislocations. As an alternative, the superlattice structure may include more than two quantum well layers, each adjacent two of which are separated by a barrier layer. As another alternative, a plurality of structures, each including two quantum well layers separated by a barrier laser may be provided, with each structure separated by a gallium arsenide buffer layer on the order of 170 to 204 angstroms thick. Where incorporated into a semiconductor diode layer as an active region, the strained superlattice structure is capable of exhibiting optical bistability.