Patent ID: 6148012
Filing Date: 2000-11-14
Classification: B82Y,H01S

Abstract:
A quantum cascade (QC) superlattice (SL) light source comprising:a core region including a QC active region which comprises a multiplicity of repeat units, each repeat unit including a unipolar radiative transition (RT) SL region and an injection/relaxation (I/R) region, each of said RT SL regions comprising a plurality of quantum well (QW) layers interleaved with a plurality of barrier layers, said QW layers having energy states characterized by upper and lower minibands, andelectrodes for applying an electric field to said source effective to cause said RT regions to generate light at energies determined by upper and lower energy levels within said upper and lower minibands, respectively, characterized in thatsaid lower miniband has at least a first level and said upper miniband has at least third and fourth energy levels, electron transitions between a first pair of said upper and lower levels generating light at a first spontaneous emission line having a center wavelength .lambda..sub.1 and a line broadening first energy and electron transitions between a second pair of said upper and lower levels generating light at a second spontaneous emission line having a center wavelength .lambda..sub.2 and a line broadening second energy,the energy separation of said center wavelengths is greater than the larger of said first and second line broadening energies, andmeans for inhibiting the relaxation of electrons from said fourth level to said third level.