Abstract: A quantum cascade laser includes a laser structure having an output face for emitting laser light in a first direction; and a lens having an entrance surface and a convex surface, the entrance surface receiving the laser light from the output face, and the convex surface emitting the laser light after being condensed by the lens. The laser structure includes a semiconductor substrate and a mesa waveguide provided on a first region of a principal surface of the semiconductor substrate, the mesa waveguide extending in the first direction. The lens includes a semiconductor and is provided on a second region of the principal surface of the semiconductor substrate. The first region and the second region are arranged in the first direction.

Abstract: A quantum cascade laser includes a laser structure having an output face for emitting laser light in a first direction, and a reflecting film provided on the output face. The laser structure includes a core layer. The output face includes an end face of the core layer. The end face includes a first region and a second region that differs from the first region. The reflecting film covers the first region and does not cover the second region.

Abstract: A quantum cascade laser includes a laser structure having an output face for emitting laser light in a first direction; and a lens having an entrance surface and a convex surface, the entrance surface receiving the laser light from the output face, and the convex surface emitting the laser light after being condensed by the lens. The laser structure includes a semiconductor substrate and a mesa waveguide provided on a first region of a principal surface of the semiconductor substrate, the mesa waveguide extending in the first direction. The lens includes a semiconductor and is provided on a second region of the principal surface of the semiconductor substrate. The first region and the second region are arranged in the first direction.

Abstract: A quantum cascade semiconductor laser includes a laser structure having a first area including an end face, a second area, and a third area; a metal layer provided on a major surface in the third area; a separation area provided on the major surface; and a reflector provided on the laser structure. The reflector includes a dielectric film and a metal reflecting film provided on the end face and the separation area. The separation area has a first portion, a second portion, and a third portion. The metal layer has an edge separated from the end face in the third area. The contact layer has an edge separated from the end face in the third area. The first portion projects more than the second portion over the semiconductor mesa. The third portion projects more than the second portion over the semiconductor mesa.

Abstract: A quantum cascade laser includes a laser structure including a semiconductor stack and a semiconductor support, the laser structure having a first end face and a second end face opposite the first end face. The semiconductor stack is disposed on the semiconductor support. The laser structure includes a semiconductor mesa and a buried region, the semiconductor mesa including a core layer, and the buried region embedding the semiconductor mesa. The laser structure includes a first region, a second region, and a third region. The third region is provided between the first region and the second region. The first region includes the first end face. The semiconductor mesa includes a first stripe portion, a second stripe portion, and a first tapered portion, respectively, in the first region, the second region, and the third region. The first stripe portion and the second stripe portion have different mesa widths.

Abstract: A surface emitting laser includes a substrate, semiconductor layers on the substrate, a light transmitting window configured to transmit laser light from the semiconductor layers, a first electrode pad, a second electrode pad, a first dummy pad, and a second dummy pad, wherein the first electrode pad, the second electrode pad, the first dummy pad, and the second dummy pad are disposed on the semiconductor layers at a place different from the light transmitting window, and wherein the substrate is classified into first through fourth regions by a straight line extending in a first direction and a straight line extending in a second direction perpendicular to the first direction, the first electrode pad being situated in the first region, the second electrode pad being situated in the second region, the first dummy pad being situated in the third region, and the second dummy pad being situated in the fourth region.

Abstract: A vertical cavity surface-emitting laser including: a substrate having a main surface; and a post structure mounted on the main surface. The post structure includes an active layer and a carrier confinement structure. The carrier confinement structure includes a first region and a second region having a higher resistivity than the first region. The first region has an edge, and a first to a third reference line segments. A first length of the first reference line segment is longest among lengths of line segments joining any two points on the edge and extending in a direction of the III-V group semiconductor. The first length is greater than a sum of a second length of the second reference line segment and a third length of the third reference line segment. The third length is smaller than the second length and is zero or more.

Abstract: A quantum cascade semiconductor laser includes a laser structure having a first area including an end face, a second area, and a third area; a metal layer provided on a major surface in the third area; a separation area provided on the major surface; and a reflector provided on the laser structure. The reflector includes a dielectric film and a metal reflecting film provided on the end face and the separation area. The separation area has a first portion, a second portion, and a third portion. The metal layer has an edge separated from the end face in the third area. The contact layer has an edge separated from the end face in the third area. The first portion projects more than the second portion over the semiconductor mesa. The third portion projects more than the second portion over the semiconductor mesa.

Abstract: A quantum cascade laser includes: a laser structure having a first region, a second region, and a third region, the first region having an end face; a high-specific resistance region on principal surfaces of the first and second regions; a metal layer on a principal surface of the third region; a dielectric film on the end face and the high-specific resistance region; and a reflective metal film on the dielectric film, the end face and the high-specific resistance region. The first to third regions are arranged in a direction of a first axis. The laser structure has a semiconductor mesa and a semiconductor base that mounts the semiconductor mesa. The high-specific resistance region has a wall or terrace providing a difference in level at a boundary between the first and second regions, the wall or terrace extending in a direction of a second axis intersecting that of the first axis.

Abstract: A vertical cavity surface-emitting laser including: a substrate having a main surface; and a post structure mounted on the main surface. The post structure includes an active layer and a carrier confinement structure. The carrier confinement structure includes a first region and a second region having a higher resistivity than the first region. The first region has an edge, and a first to a third reference line segments. A first length of the first reference line segment is longest among lengths of line segments joining any two points on the edge and extending in a [1-10] direction of the III-V group semiconductor. The first length is greater than a sum of a second length of the second reference line segment and a third length of the third reference line segment. The third length is smaller than the second length and is zero or more.

Abstract: A quantum cascade laser comprises: a laser structure including a first region, a second region, and a third region, the first region having an end face; a high-specific resistance region disposed on the first and second regions; a metal layer disposed on the third region; a dielectric film disposed on the end face and the high-specific resistance region; and a reflective metal film disposed on the dielectric film, the end face and the high-specific resistance region. The first to third regions are arranged in order in a direction of a first axis. The laser structure has a terrace on a boundary between the second and third regions, and the laser structure includes a semiconductor mesa and a conductive base. The semiconductor mesa has a core layer, and the conductive base mounts the semiconductor mesa. The high-specific resistance region has a specific resistance larger than that of the conductive base.

Abstract: A quantum cascade laser includes: a substrate having a principal surface, a back surface, and a substrate end face, the substrate end face extending along a reference plane intersecting a second direction which intersects the first direction; a semiconductor laminate having a laminate end face extending along the reference plane; a first electrode disposed on the semiconductor laminate; a second electrode disposed on the substrate; a first insulating film disposed on the laminate end face and the first electrode; a metal film disposed on the first insulating film, the laminate end face, the substrate end face, and the second electrode; and a second insulating film disposed on the first electrode, the second insulating film having a part on the first electrode between the metal film and the semiconductor laminate. On the first electrode, the second insulating film has a thickness larger than that of the first insulating film.

Abstract: A quantum cascade laser includes: a substrate having a principal surface, an back surface, and a substrate end face, the substrate end face extending along a reference plane intersecting a second direction which intersects the first direction; a semiconductor laminate having a laminate end face extending along the reference plane; a first electrode disposed on the semiconductor laminate; a second electrode disposed on the substrate; a first insulating film disposed on the laminate end face and the first electrode; a metal film disposed on the first insulating film, the laminate end face, the substrate end face, and the second electrode; and a second insulating film disposed on the first electrode, the second insulating film having a part on the first electrode between the metal film and the semiconductor laminate. On the first electrode, the second insulating film has a thickness larger than that of the first insulating film.

Abstract: A quantum cascade laser includes: a laser structure having a first region, a second region, and a third region, the first region having an end face; a high-specific resistance region disposed on a principal surfaces of the first and second regions; a metal layer disposed on a principal surface of the third region; a dielectric film disposed on the end face and the high-specific resistance region; and a reflective metal film disposed on the dielectric film, the end face and the high-specific resistance region. The first to third regions are arranged in a direction of a first axis. The laser structure has a semiconductor mesa and a semiconductor base. The semiconductor base mounts the semiconductor mesa. The dielectric film has a difference in level at a boundary between the first and second regions, and the terrace extends in a direction of a second axis intersecting that of the first axis.

Abstract: A quantum cascade laser comprises: a laser structure including a first region, a second region, and a third region, the first region having an end face; a high-specific resistance region disposed on the first and second regions; a metal layer disposed on the third region; a dielectric film disposed on the end face and the high-specific resistance region; and a reflective metal film disposed on the dielectric film, the end face and the high-specific resistance region. The first to third regions are arranged in order in a direction of a first axis. The laser structure has a terrace on a boundary between the second and third regions, and the laser structure includes a semiconductor mesa and a conductive base. The semiconductor mesa has a core layer, and the conductive base mounts the semiconductor mesa. The high-specific resistance region has a specific resistance larger than that of the conductive base.

Abstract: A surface emitting semiconductor laser includes a post disposed on a substrate, the post including an active layer and a distributed Bragg reflector; a first insulating layer disposed on side and top surfaces of the post and on the substrate, the first insulating layer having an opening on the top surface of the post; an electrode disposed in the opening of the first insulating layer; an electric conductor including a pad electrode on the first insulating layer, the electric conductor extending on the first insulating layer to the electrode; and a second insulating layer disposed on the first insulating layer, the electrode, and the electric conductor so as to cover the electrode in the opening of the first insulating layer, the second insulating layer having an opening on the pad electrode, the opening of the second insulating layer having an edge on a top surface of the pad electrode.

Abstract: A surface emitting semiconductor laser includes a post disposed on a substrate, the post including an active layer and a distributed Bragg reflector; a first insulating layer disposed on side and top surfaces of the post and on the substrate, the first insulating layer having an opening on the top surface of the post; an electrode disposed in the opening of the first insulating layer; an electric conductor including a pad electrode on the first insulating layer, the electric conductor extending on the first insulating layer to the electrode; and a second insulating layer disposed on the first insulating layer, the electrode, and the electric conductor so as to cover the electrode in the opening of the first insulating layer, the second insulating layer having an opening on the pad electrode, the opening of the second insulating layer having an edge on a top surface of the pad electrode.

Abstract: A quantum cascade laser includes a laser structure including laser waveguide structures and a first terrace region; first electrodes; pad electrodes; and wiring metal conductors. The laser structure includes first, second and third regions arranged in a direction of a first axis. The third region is disposed between the first and second regions. The first region has a first end facet disposed at a boundary between the first and third regions. The first end facet extends in a direction intersecting with the first axis. The second region has a second end facet disposed at a boundary between the second and third regions. The second region includes the laser structure. The pad electrodes are disposed on the first terrace region. The first electrodes are disposed on the laser waveguide structures. Each of the pad electrodes is connected to one of the first electrodes through one of the wiring metal conductors.

Abstract: A quantum cascade laser integrated device includes: first and second lower semiconductor mesas extending in a direction of a first axis; a covering region disposed on top and side faces of the first and second lower semiconductor mesas, and including first and second upper semiconductor mesas, the first and second upper semiconductor mesas extending in the direction of the first axis on the first and second lower semiconductor mesas, respectively; and first and second electrodes respectively disposed on the upper semiconductor mesas, the first lower semiconductor mesa and the second lower semiconductor mesa each including a quantum cascading core layer, the covering region including a current blocking semiconductor region embedding the first and second lower semiconductor mesas, and a first conductivity-type semiconductor region disposed on the first and second lower semiconductor mesas and the current blocking semiconductor region, and the first conductivity-type semiconductor region including an upper cladd

Abstract: A quantum cascade laser includes a substrate having first and second substrate regions arranged along a first axis; a laser structure body including a laser body region having laser waveguide structures extending along the first axis, the laser structure body including first and second regions respectively including the first and second substrate regions, the laser body region having an end facet located at a boundary between the first and second regions, the second region including a terrace extending along the first axis from a bottom edge of the end facet; a plurality of first electrodes disposed on the laser waveguide structures; a plurality of pad electrodes disposed on the terrace; and a plurality of wiring metal bodies each of which includes a first portion on the terrace and a second portion on the end facet. The pad electrodes are connected with the first electrodes through the wiring metal bodies, respectively.