Disclosed herein are self-mixing interferometry (SMI) sensors, such as may include vertical cavity surface emitting laser (VCSEL) diodes and resonance cavity photodetectors (RCPDs). Structures for the VCSEL diodes and RCPDs are disclosed. In some embodiments, a VCSEL diode and an RCPD are laterally adjacent and formed from a common set of semiconductor layers epitaxially formed on a common substrate. In some embodiments, a first and a second VCSEL diode are laterally adjacent and formed from a common set of semiconductor layers epitaxially formed on a common substrate, and an RCPD is formed on the second VCSEL diode. In some embodiments, a VCSEL diode may include two quantum well layers, with a tunnel junction layer between them. In some embodiments, an RCPD may be vertically integrated with a VCSEL diode.

In some implementations, a vertical cavity surface emitting laser (VCSEL) device includes a substrate; a first mirror disposed over the substrate; a bonding layer disposed over the first mirror; and an active region disposed over the bonding layer. The substrate is a gallium arsenide (GaAs) substrate, and the active region is an indium phosphide (InP)-based active region.

A vertical-cavity surface-emitting laser (VCSEL) may include a substrate. The VCSEL may include a bottom mirror structure over the substrate. The VCSEL may include a first dilute nitride active region over the bottom mirror structure. The VCSEL may include a tunnel junction over the first dilute nitride active region. The VCSEL may include a second dilute nitride active region over the tunnel junction. The VCSEL may include a top mirror structure over the second dilute nitride active region.

A Vertical Cavity Surface Emitting Laser (VCSEL) including a light emitting III-nitride active region including quantum wells (QWs), wherein each of the quantum wells have a thickness of more than 8 nm, a cavity length of at least 7 λ, or at least 20 λ, where lambda is a peak wavelength of the light emitted from the active region, layers with reduced surface roughness, a tunnel junction intracavity contact. The VCSEL is flip chip bonded using In—Au bonding. This is the first report of a VCSEL capable of continuous wave operation.

A photonic crystal surface-emitting laser includes a substrate, an n-type cladding layer, an active layer, a photonic crystal structure, a p-type cladding layer, an n-type semiconductor layer and a meta-surface structure. The n-type cladding layer is disposed over the substrate. The active layer is disposed over the n-type cladding layer. The photonic crystal structure is disposed over the active layer. The p-type cladding layer is disposed over the photonic crystal structure. The n-type semiconductor layer is disposed over the p-type cladding layer. The meta-surface structure disposed on a surface of the n-type semiconductor layer away from the p-type cladding layer.

Methods for fabricating vertical cavity surface emitting lasers (VCSELs) on a large wafer are provided. An un-patterned epi layer form is bonded onto a first reflector form. The first reflector form includes a first reflector layer and a wafer of a first substrate type. The un-patterned epi layer form includes a plurality of un-patterned layers on a wafer of a second substrate type. The first and second substrate types have different thermal expansion coefficients. A resulting bonded blank is substantially non-varying in a plane that is normal to an intended emission direction of the VCSEL. A first regrowth is performed to form first regrowth layers, some of which are patterned to form a tunnel junction pattern. A second regrowth is performed to form second regrowth layers. A second reflector form is bonded onto the second regrowth layers, wherein the second reflector form includes a second reflector layer.

An emitter may include a substrate, a conductive layer on at least a bottom surface of a trench, and a first metal layer to provide a first electrical contact of the emitter on an epitaxial side of the substrate. The first metal layer may be within the trench such that the first metal layer contacts the conductive layer within the trench. The emitter may further include a second metal layer to provide a second electrical contact of the emitter on the epitaxial side of the substrate, and an isolation implant to block lateral current flow between the first electrical contact and the second electrical contact.

Provided is a semiconductor laser diode including multiple active layers and a grating layer. The semiconductor laser diode includes two (or more than two) active layers, a grating layer, and a tunnel junction. The grating layer and the tunnel junction are provided between the two active layers. The tunnel junction is electrically connected to the two active layers, and the two active layers share and are optically coupled to the grating layer, thereby improving the external quantum efficiency and slope efficiency of the semiconductor laser diode.

A vertical cavity surface emitting laser (VCSEL) device may include a substrate layer and a first set of epitaxial layers, for a first VCSEL, disposed on the substrate layer. The first set of epitaxial layers may include a first set of mirrors and at least one first active layer. The VCSEL device may include a second set of epitaxial layers, for a second VCSEL, disposed on the first set of epitaxial layers for the first VCSEL. The second set of epitaxial layers may include a second set of mirrors and at least one second active layer. The first VCSEL and the second VCSEL may be configured to emit light in a light emission direction. The at least one first active layer of the first VCSEL may be offset in the light emission direction from the at least one second active layer of the second VCSEL.

A light-emitting element array includes a substrate, plural light-emitting elements arranged on the substrate, plural constriction grooves being provided in a periphery of each of the plural light-emitting elements and forming a current constriction layer that constricts a current flowing through a light-emitting layer by oxidizing the light-emitting layer, and a block separation portion that is provided in a curved shape so as to include at least one inflection point at which a sign of curvature changes along each of positions where the plural light-emitting elements are arranged, and separates the plural light-emitting elements into plural blocks.