Interband Quantum Well Cascade Laser, with a Blocking Quantum Well for Improved Quantum Efficiency
Patent, Filed 1 Nov 96, patented 25 Aug 98
DEPARTMENT OF THE NAVY WASHINGTON DC
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A gain region for an interband quantum well laser includes a an emitter region of semiconductor material having at least one conduction subband and at least one valence subband, these subbands being spaced apart by an energy band-gap b a collector region of semiconductor material having at least one conduction subband and at least one valence subband, these subbands spaced apart by an energy band-gap c a type-I or type-II active region, and d a blocking quantum well region of semiconductor material between the active region and the collector region, for keeping electrons in the active region from tunneling or scattering into the collector region, but allowing electrons in the highest valence subband in the active region to pass into the collector region. Another aspect of the invention is a cascade laser made from a stack of these gain regions, connected in series, optical cladding regions at opposing ends of the stack, and a voltage source for applying a bias voltage to the stack, and an optical cavity perpendicular to the stacking axis fabricated by cleaving or other means.
- Electrooptical and Optoelectronic Devices
- Solid State Physics