A nitride semiconductor multilayer structure includes a first nitride semiconductor layer; a second nitride semiconductor layer; and a third nitride semiconductor layer formed between the first nitride semiconductor layer and the second nitride semiconductor layer. The third nitride semiconductor layer includes a first region and a second region that surrounds the first region in a same plane, and an indium content of the second region is lower than an indium content of the first region.

Optical devices and methods of manufacturing and operating such optical devices. In an embodiment, an optical device includes a substrate, a multi-layer structure having a first surface in contact with a first surface of the substrate, a first mirror disposed over a second surface of the multi-layer structure, a second mirror disposed over a second surface of the substrate, an intermediate mirror within the multi-layer structure, and an optical gain structure within the multi-layer structure. The device may include a first optically resonant cavity within the multi-layer structure, bounded by the first mirror and the intermediate mirror, where the first optically resonant cavity includes the optical gain structure. The device may further include a second optically resonant cavity, bounded by the first and second mirrors, where the second optically resonant cavity includes the first optically resonant cavity, the second optically reflective layer, and the substrate.

A semiconductor laser including: a first mirror layer; a second mirror layer; an active layer, a current confinement layer, a first region, and a second region, in which the first mirror layer, the second mirror layer, the active layer, the current confinement layer, the first region, and the second region constitute a laminated body, the first region and the second region constitute an oxidized region of the laminated body, in a plan view, the laminated body includes a first part, a second part, and a third part disposed between the first part and the second part and resonating light generated in the active layer, and in a plan view, at least at a part of the third part, W1>W3 and W2>W3, W1 is a width of the oxidized region of the first part, W2 is a width of the oxidized region of the second part, and W.sub.3 is a width of the oxidized region of the third part.

Optical devices and methods of manufacturing and operating such optical devices. In an embodiment, an optical device includes a substrate, a multi-layer structure having a first surface in contact with a first surface of the substrate, a first mirror disposed over a second surface of the multi-layer structure, a second mirror disposed over a second surface of the substrate, an intermediate mirror within the multi-layer structure, and an optical gain structure within the multi-layer structure. The device may include a first optically resonant cavity within the multi-layer structure, bounded by the first mirror and the intermediate mirror, where the first optically resonant cavity includes the optical gain structure. The device may further include a second optically resonant cavity, bounded by the first and second mirrors, where the second optically resonant cavity includes the first optically resonant cavity, the second optically reflective layer, and the substrate.

A VCSEL can include: an elliptical oxide aperture in an oxidized region that is located between an active region and an emission surface, the elliptical aperture having a short radius and a long radius with a radius ratio (short radius)/(long radius) being between 0.6 and 0.8, the VCSEL having a relative intensity noise (RIN) of less than −140 dB/Hz. The VCSEL can include an elliptical emission aperture having the same dimensions of the elliptical oxide aperture. The VCSEL can include an elliptical contact having an elliptical contact aperture therein, the elliptical contact being around the elliptical emission aperture. The elliptical contact can be C-shaped. The VCSEL can include one or more trenches lateral of the oxidized region, the one or more trenches forming an elliptical shape, wherein the oxidized region has an elliptical shape. The one or more trenches can be trapezoidal shaped trenches.

Within examples, a laser includes a first electrode and a second electrode; a first transport layer and a second transport layer that are between the first electrode and the second electrode; a gain layer positioned between the first transport layer and the second transport layer, where the gain layer comprises a material having a Perovskite crystal structure; and a substrate on which the first electrode, the second electrode, the first transport layer, the second transport layer, and the gain layer are formed, where a distributed feedback (DFB) waveguide is formed within the first transport layer, and where the laser is configured such that a current flowing through the gain layer between the first electrode and the second electrode causes the gain layer to emit coherent light. Examples also include methods for fabricating the laser, as well as additional lasers and methods for forming those lasers.

Disclosed herein is a system comprising: an optical system with a focal plane; an apparatus at the focal plane; a filter; wherein the apparatus comprises an array of vertical-cavity surface-emitting lasers (VCSELs) on a first substrate and an array of detectors on a second substrate, the detectors configured to detect laser beams that are emitted by the VCSELs and backscattered by an object; wherein the first substrate is mounted to the second substrate and is configured to allow the laser beams that are emitted by the VCSELs and backscattered by the object to transmit through the first substrate and reach the detectors; wherein the filter is configured to prevent light other than the laser beams from passing.

A VCSEL device includes a semiconductor substrate; a current conductive layer on the semiconductor substrate; a N-type Bragg reflector layer in contact with the current conductive layer; a P-type Bragg reflector layer above the N-type Bragg reflector layer; an active emitter layer; a current restriction layer, wherein the current restriction layer has a current restriction hole; a metal layer in contact with the semiconductor substrate, the metal layer has a through hole aligned with the current restriction hole; a P-type bonding pad in ohmic contact with the P-type Bragg reflector layer, and a portion of the P-type bonding pad is aligned with the current restriction hole and the through hole; and a N-type bonding pad in ohmic contact with the current conductive layer, and electrically separated from the P-type bonding pad. The P-type bonding pad and the N-type bonding pad are at a same side of the semiconductor substrate.

Provided is a high-power vertical cavity surface emitting laser diode (VCSEL), including a first epitaxial region, an active region and a second epitaxial region. One of the first epitaxial region and the second epitaxial region is an N-type epitaxial region, and the other of the first epitaxial region and the second epitaxial region includes a PN junction. The PN junction includes a P-type epitaxial layer, a tunnel junction and an N-type epitaxial layer. The tunnel junction is located between the P-type epitaxial layer and the N-type epitaxial layer, and the P-type epitaxial layer of the PN junction is closest to the active region.

A surface emitting laser includes a lower reflector layer, an active layer , an upper reflector layer , and a wiring. The lower reflector layer, the active layer, and the upper reflector layer form a mesa, a terrace, and a connecting portion. A first groove is provided between the mesa and the terrace. The connecting portion connects the mesa and the terrace, and extends in a direction inclined from <011> direction of the substrate. A high-resistance region is formed in the terrace, in the connecting portion, and in a peripheral portion of the mesa. The wiring is provided on top surfaces of the terrace, the connecting portion, and the mesa. The mesa includes an oxide region extending from a side surface of the mesa and a current confinement structure including an aperture surrounded by the oxide region.