Dual polarization laser diode with quaternary material system
AssigneeXerox Corporation
InventorsThomas L. Paoli, David P. Bour
Life of this patent
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Abstract
A semiconductor laser source using a strained active layer of GaAsP or InGaAsP or AlGaAsP to obtain semiconductor laser sources that emit TM-polarized light in the wavelength range of 600-870 nm. Preferably, the active layer is flanked by confining layers of AlGaAs or (AlGa).sub.0.52 In.sub.0.48 P. The active layer under proper conditions can also emit TE-polarized light. Hence, arrays of side-by-side orthoginally-polarized emitters, or switchable polarized emitters are feasible.
Claims27
A laser diode comprising:
- (a) a crystalline substrate of a III-V alloy 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 quaternary alloy 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 tensile-strained such that said active layer has a third bandgap when strained that is smaller than the second bandgap,
- (c) electrodes for passing current through the active layer to thereby cause TM-polarized laser emission in said active layer at a wavelength exceeding 600 nm.
A laser diode comprising:
- (a) a crystalline substrate of a III-V alloy having a first lattice constant and a first bandgap,
- (b) a crystalline active layer deposited over said substrate, said active layer comprising a GaAsP alloy 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 tensile-strained such that said active layer has a third bandgap when strained that is smaller than the second bandgap,
- (c) electrodes for passing current through the active layer to thereby cause TM-polarized laser emission in said active layer at a wavelength exceeding 600 nm.
A polarization-switchable semiconductor laser, comprising:
- (a) a semiconductor body having an active portion of a material exhibiting heavy hole and light hole band edges and capable of lasing and providing TE-mode polarized gain from heavy hole band transitions and TM-mode polarized gain from light hole band transitions,
- (b) a QW laser structure in said active portion,
- (c) electrodes for introducing carriers into the laser structure,
- (d) optical reflectors associated with the laser structure,
- (e) means connected to the laser structure for causing it selectively to lase in either its TE-mode or its TM-mode,
- (f) the material of said active portion comprising a tensile-strained alloy of InGaAsP, AlGaAsP, or GaAsP.
A dual polarization, multi-beam emitting semiconductor QW laser, comprising:
- (a) a semiconductor body having first and second side-by-side active portions of a material exhibiting heavy hole and light hole band edges and capable of lasing and providing TE-mode polarized gain from heavy hole band transitions and TM-mode polarized gain from light hole band transitions, said first and second active portions forming adjacent first and second QW laser structures emitting, respectively, in the TE-mode and TM-mode,
- (b) electrode for introducing carriers into the active portions,
- (c) optical reflectors associated with each laser structure,
- (d) means connected to the adjacent laser structures for selectively activating same causing the first to lase in its TE-mode and the second to lase in its TM-mode,
- (e) said active portions comprising a tensile-strained alloy of InGaAsP, AlGaAsP, or GaAsP.
Dependencies are inferred from the claim text.