US 11,843,224 B2
Quantum cascade laser
Takashi Kato, Osaka (JP)
Assigned to SUMITOMO ELECTRIC INDUSTRIES, LTD., Osaka (JP)
Filed by SUMITOMO ELECTRIC INDUSTRIES, LTD., Osaka (JP)
Filed on Aug. 3, 2021, as Appl. No. 17/392,305.
Claims priority of application No. 2020-140142 (JP), filed on Aug. 21, 2020.
Prior Publication US 2022/0059995 A1, Feb. 24, 2022
Int. Cl. H01S 5/34 (2006.01); H01S 5/343 (2006.01)
CPC H01S 5/3406 (2013.01) [H01S 5/3402 (2013.01); H01S 5/34313 (2013.01); H01S 5/34346 (2013.01)] 4 Claims
OG exemplary drawing
 
1. A quantum cascade laser comprising:
a substrate that includes a group III-V compound semiconductor; and
a core region that is provided on the substrate and that includes a group III-V compound semiconductor,
wherein the core region includes a plurality of unit structures that are stacked on top of one another,
wherein each of the plurality of unit structures includes an active layer and an injection layer,
wherein the injection layer includes at least one strain-compensated layer and at least one lattice-matched layer, the at least one strain-compensated layer including a first well layer and a first barrier layer and the at least one lattice-matched layer including a second well layer and a second barrier layer,
wherein the first well layer has a lattice constant larger than a lattice constant of the substrate,
wherein the first barrier layer has a lattice constant smaller than the lattice constant of the substrate,
wherein the second well layer and the second barrier layer each have a lattice constant that is lattice-matched to the substrate,
wherein the at least one strain-compensated layer includes a plurality of strain-compensated layers,
wherein the at least one lattice-matched layer is disposed between the plurality of strain-compensated layers,
wherein an absolute value of a strain of the second well layer with respect to the substrate is 0.3% or less, and
wherein an absolute value of a strain of the second barrier layer with respect to the substrate is 0.3% or less.