Polarization-tunable optoelectronic devices
AssigneeInternational Business Machines Corporation
InventorsEmilio E. Mendez, Doyeol Ahn
Life of this patent
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Abstract
A strained-layer quantum well (QW) or multi-quantum well (MQW) semiconductor laser device (10) having a polarization that is switchable between the TE and the TM modes by an electric field that is externally applied, via an electrode (22) perpendicularly to the layer (16) or layers of the quantum well. The polarization switching is a direct consequence of a valence-band reversal induced by the electric field in the strained-layer quantum well. An inversion population is maintained during the switching process, resulting in rapid switching times.
Claims27
A semiconductor optoelectronic device comprising:
- a quantum well region comprised of a first semiconductor material and a second semiconductor material, the second semiconductor material having a lattice constant that differs from a lattice constant of the first semiconductor material by an amount sufficient to strain the quantum well region such that electromagnetic radiation generated within the quantum well region has a TM polarization;
- and
- means for impressing an electric field across the quantum well region, the electric field having a magnitude above a threshold magnitude such that electromagnetic radiation generated within the quantum well region has, during a time that the electric field is impressed there across, a TE polarization.
A semiconductor laser comprising:
- a substrate;
- a first semiconductor material disposed above a surface of the substrate;
- a quantum well region formed adjacent to the first semiconductor material, the quantum well region being comprised of at least one layer of a second semiconductor material that has a lattice constant that differs from a lattice constant of the first semiconductor material by an amount sufficient to compressively strain the quantum well region such that electromagnetic radiation generated within the quantum well region has a TM polarization;
- and
- means for impressing an electric field perpendicularly across the at least one layer of the quantum well region, the electric field having a magnitude sufficient for switching the polarization of the electromagnetic radiation from the TM polarization to a TE polarization.
A method of operating a semiconductor laser comprising the steps of:
- providing a semiconductor laser having one or more quantum wells, the one or more quantum wells having a uniaxial compressive stress applied thereto, a magnitude of the compressive stress being in excess of a critical value (S.sub.c);
- operating the semiconductor laser to generate electromagnetic radiation having a TM polarization;
- and
- applying an electric field perpendicularly to the one or more quantum wells, the electric field having a magnitude above a threshold magnitude for causing the semiconductor laser to generate electromagnetic radiation having a TE polarization.
Dependencies are inferred from the claim text.