# US 10,312,667 B2 · Quantum cascade laser > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,312,667 B2 - Document ID: US10312667B2 - Status: Granted - Kind: B2 - Application number: 15/834,753 - Filed: 2017-12-07 - Published: 2018-06-14 - Granted: 2019-06-04 - Earliest claimed: 2016-12-08 - Assignees: Sumitomo Electric Industries, Ltd. - Applicants: Sumitomo Electric Industries, Ltd. - Inventors: Jun-ichi Hashimoto - Web page: https://patentgrep.com/patent/US10312667B2 ## CPC - H01S 5/3402: {intersubband lasers, e.g. transitions within the conduction or valence bands} - H01S 5/12: the resonator having a periodic structure, e.g. in distributed feedback [DFB] lasers (comprising a photonic bandgap structure H01S5/11; surface-emitting lasers H01S5/18) - H01S 5/164: {with window regions comprising semiconductor material with a wider bandgap than the active layer} - H01S 5/2226: {semiconductors with a specific doping} - H01S 5/227: Buried mesa structure {; Striped active layer} - B82Y 20/00: Nanooptics, e.g. quantum optics or photonic crystals - H01S 5/0202: {Cleaving} - H01S 5/0281: {Coatings made of semiconductor materials} - H01S 5/2224: {semi-insulating semiconductors} - H01S 5/2275: {mesa created by etching} - H01S: DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL - B82Y: SPECIFIC USES OR APPLICATIONS OF NANOSTRUCTURES; MEASUREMENT OR ANALYSIS OF NANOSTRUCTURES; MANUFACTURE OR TREATMENT OF NANOSTRUCTURES ## Abstract A quantum cascade laser includes a laser structure including first and second end faces, the laser structure including a semiconductor laminate region and a first embedding semiconductor region. The laser structure includes first and second regions arranged in a direction of a first axis extending from the first to second end faces. Each of the first and second regions includes the semiconductor laminate region. The semiconductor laminate region of the first region has a first recess. The semiconductor laminate region of the second region has a semiconductor mesa. The first recess and the semiconductor mesa extend in the direction of the first axis, and are aligned with each other. The semiconductor mesa has an end face extending in a direction of a second axis intersecting the first axis. The first embedding semiconductor region is disposed in the first recess so as to embed the end face of the semiconductor mesa. ## Claims ### Claim 1 A quantum cascade laser comprising a laser structure including a first end face and a second end face opposite to the first end face, the laser structure including a substrate having a principal surface, a semiconductor laminate region, and a first embedding semiconductor region, the semiconductor laminate region and the first embedding semiconductor region being disposed on the principal surface of the substrate, the laser structure including a first region and a second region that are arranged in a direction of a first axis extending from the first end face to the second end face, each of the first region and the second region including the semiconductor laminate region, the semiconductor laminate region of the first region having a recess extending in the direction of the first axis, the semiconductor laminate region of the second region having a semiconductor mesa extending in the direction of the first axis, the semiconductor mesa having a core layer, the semiconductor mesa having an end face extending in a direction of a second axis intersecting the first axis, the semiconductor mesa and the recess being aligned with each other, the first embedding semiconductor region being disposed in the recess so as to embed the end face of the semiconductor mesa, wherein the recess is defined by first and second side faces of the semiconductor laminate region and the end face of the semiconductor mesa, and the first embedded semiconductor region is in contact with the end face of the semiconductor mesa and the first and the second side faces. ### Claim 2 (depends on 1) The quantum cascade laser according to claim 1, wherein the semiconductor laminate region includes a first laminate structure and a second laminate structure each extending in the direction of the first axis, in the second region, the semiconductor mesa is disposed between the first laminate structure and the second laminate structure, in the first region, the first laminate structure and the second laminate structure respectively provide the first and the second side faces of the semiconductor laminate region to define the recess, the second region of the laser structure includes a second embedding semiconductor region, and in the second region, the second embedding semiconductor region is disposed between the first laminate structure and the semiconductor mesa and between the second laminate structure and the semiconductor mesa. ### Claim 3 (depends on 2) The quantum cascade laser according to claim 2, wherein the semiconductor laminate region of the first region includes a connecting laminate structure, and the first laminate structure and the second laminate structure reach the connecting laminate structure. ### Claim 4 (depends on 1) The quantum cascade laser according to claim 1, wherein the first embedding semiconductor region and the semiconductor laminate region of the first region reach the first end face. ### Claim 5 (depends on 1) The quantum cascade laser according to claim 1, wherein the first embedding semiconductor region includes at least one of undoped semiconductor or semi-insulating semiconductor. ### Claim 6 (depends on 1) The quantum cascade laser according to claim 1, wherein the first embedding semiconductor region is made of at least one of InP or InGaAsP. ### Claim 7 (depends on 1) The quantum cascade laser according to claim 1, wherein the laser structure further includes a current blocking region disposed on a side face of the semiconductor mesa, the current blocking region embedding the semiconductor mesa, and the first embedding semiconductor region is made of substantially the same material as that of the current blocking region. ### Claim 8 (depends on 1) The quantum cascade laser according to claim 1, wherein the substrate has a ridge portion on which the semiconductor mesa is disposed, the substrate is made of semiconductor having cleavability, the semiconductor laminate region is made of semiconductor having cleavability, and the first embedding semiconductor region is made of semiconductor having cleavability. ### Claim 9 (depends on 1) The quantum cascade laser according to claim 1, wherein the first and the second end faces each have a cleavage plane. ### Claim 10 A quantum cascade laser comprising a laser structure comprising a first end face and a second end face opposite to the first end face, the laser structure including a substrate having a principal surface, a semiconductor laminate region, and a first embedding semiconductor region, the semiconductor laminate region and the first embedding semiconductor region being disposed on the principal surface of the substrate, the laser structure including a first region and a second region that are arranged in a direction of a first axis extending from the first end face to the second end face, each of the first region and the second region including the semiconductor laminate region, the semiconductor laminate region of the first region having a recess extending in the direction of the first axis, the semiconductor laminate region of the first region having a first side face and a second side face that extend in the direction of the first axis to form the recess, the semiconductor laminate region of the second region having a semiconductor mesa extending in the direction of the first axis, the semiconductor mesa having a core layer, the semiconductor mesa having an end face extending in a direction of a second axis intersecting the first axis, the semiconductor mesa and the recess being aligned with each other, the first embedding semiconductor region being disposed in the recess so as to embed the end face of the semiconductor mesa and the first and the second side faces of the semiconductor laminate region, and the semiconductor mesa and the semiconductor laminate region supporting the first embedding semiconductor region on the end face of the semiconductor mesa and the first and the second side faces of the semiconductor laminate region. ### Claim 11 (depends on 10) The quantum cascade laser according to claim 10, wherein the semiconductor laminate region includes a first laminate structure and a second laminate structure each extending in the direction of the first axis, in the second region, the semiconductor mesa is disposed between the first laminate structure and the second laminate structure, in the first region, the first laminate structure and the second laminate structure respectively provide the first and the second side faces of the semiconductor laminate region to define the recess, the second region of the laser structure includes a second embedding semiconductor region, and in the second region, the second embedding semiconductor region is disposed between the first laminate structure and the semiconductor mesa and between the second laminate structure and the semiconductor mesa. ### Claim 12 (depends on 10) The quantum cascade laser according to claim 10, wherein the semiconductor laminate region of the first region includes a connecting laminate structure, and the first laminate structure and the second laminate structure reach the connecting laminate structure. ### Claim 13 (depends on 10) The quantum cascade laser according to claim 10, wherein the first embedding semiconductor region and the semiconductor laminate region of the first region reach the first end face. ### Claim 14 (depends on 10) The quantum cascade laser according to claim 10, wherein the first embedding semiconductor region includes at least one of undoped semiconductor or semi-insulating semiconductor in contact with the end face of the semiconductor mesa and the first and the second side faces of the semiconductor laminate region. ### Claim 15 (depends on 10) The quantum cascade laser according to claim 10, wherein the laser structure further includes a current blocking region, the current blocking region embeds the semiconductor mesa, and the current blocking region includes at least one of undoped semiconductor or semi-insulating semiconductor in contact with a side face of the semiconductor mesa. ### Claim 16 (depends on 10) The quantum cascade laser according to claim 10, further comprising an electrode on the semiconductor mesa and connected to a top of the semiconductor mesa. ### Claim 17 (depends on 16) The quantum cascade laser according to claim 16, wherein the electrode is not in contact with the first embedding semiconductor region. ### Claim 18 (depends on 10) The quantum cascade laser according to claim 10, further comprising an insulating film, the insulating film being disposed on the first embedding semiconductor region and the semiconductor laminate region of the first region. ### Claim 19 (depends on 16) The quantum cascade laser according to claim 16, wherein the semiconductor mesa includes a lower cladding layer, a grating layer, and an upper cladding layer, and the lower cladding layer, the grating layer, and the upper cladding layer terminate at the first end face. ### Claim 20 (depends on 10) The quantum cascade laser according to claim 10, wherein the first and the second end faces each have a cleavage plane.