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US 5,383,211 AGranted
TM-polarized laser emitter using III-V alloy with nitrogen
AssigneeXerox Corporation
InventorsChris Van de Walle, David P. Bour
Life of this patent
Estimating the term…
Abstract
A semiconductor laser source using a strained active layer of InGaAsN, introduced by the addition of N in the alloy, to obtain semiconductor laser sources that emit TM-polarized light in the wavelength range above 850 nm. The presence of N in the alloy reduces the lattice constant and produces the desired strain effect, i.e., biaxial tension which raises the light hole band (yielding TM polarization) and produces a narrowing of the band gap. Adding In can reduce the strain in the alloy while maintaining the desired band gap and light-hole/heavy-hole ordering.
Claims12
A laser diode comprising:
- (a) a crystalline substrate of GaAs having a first lattice constant and a first bandgap,
- (b) a crystalline active layer deposited over said substrate, said active layer comprising a III-V alloy and having a second lattice constant smaller than said first lattice constant and a second bandgap when unstrained, said active layer when deposited over said substrate being strained such that said active layer has a third bandgap when strained that is smaller than the first bandgap,
- (c) electrodes for injecting carriers into the active layer to thereby cause laser emission in said active layer at a wavelength exceeding the wavelength of laser emission of a material having the first bandgap.
A laser diode comprising:
- (a) a crystalline substrate of a III-V alloy comprising GaAs and having a first lattice constant and a first bandgap,
- (b) a crystalline active layer deposited over said substrate, said active layer comprising a III-V alloy with the addition of nitrogen such that said active layer has a second lattice constant smaller than said first lattice constant and a second bandgap when unstrained, said active layer when deposited over said substrate being strained such that said active layer has a third bandgap when tensile-strained, that is smaller than the first bandgap,
- (c) electrodes for passing current through the active layer to thereby cause laser emission from said active layer at a wavelength exceeding 850 nm.
Dependencies are inferred from the claim text.