Quantum parallel laser: A unipolar superlattice interminiband laser

Designs are given for parallel (rather than cascade) intersubband lasing in superlattice structures of group IV and III-V materials, Structures with population inversion due to coupled wells have minibandwidths too narrow for coherent transport and the incoherent interperiod rates are too small for population of a significant number of periods, A single-well period with local population inversion gives operation in the coherent regime, An example is given for the III-V materials. Both SiGe-Si and Si-ZnS are discussed for intersubband lasing at 1-20 mu m.