A laser includes an active region surrounded by first and second waveguide layers. Two or more mask openings are formed within a dielectric layer on a surface parallel to the active region. A refractive grating is formed on the dielectric mask openings and includes three-dimensional grating features spaced apart in the light-propagation direction of the laser. The refractive grating provides modulation of a real part of the effective refractive index of the laser and modulation of the imaginary part is provided by modulation of the current flow through the mask openings.

A semiconductor laser diode includes a semiconductor layer sequence with an active layer having a main extension plane and that generates light in an active region and emits light via a light outcoupling surface during operation, wherein the active region extends from a rear surface opposite the light outcoupling surface to the light outcoupling surface along a longitudinal direction, the semiconductor layer sequence includes a trench structure having at least one trench or a plurality of trenches on at least one side laterally next to the active region, and each trench of the trench structure extends in a longitudinal direction and projects from a top side of the semiconductor layer sequence in a vertical direction into the semiconductor layer sequence, and the trench structure varies in a lateral and/or vertical and/or longitudinal direction with respect to properties of the at least one trench or the plurality of trenches.

The present disclosure relates to a three-dimensional cylindrical cavity-type laser system capable of supporting circumferential radial emission. A cylindrical ring waveguide provides optical confinement in the radial and axial dimensions thereby supporting a plurality of radial modes, one of a plurality of axial modes and a plurality of degenerate azimuthal modes. These modes constitute a set of traveling wave modes which propagate around the cylindrical ring waveguide possessing various degrees of optical confinement as quantified by their respective Q-factors. Index tailoring is used to tailor the radial refractive index profile and geometry of the waveguide to support radial modes possessing Q-factors capable of producing efficient radial emission, while gain tailoring is used to define a gain confining region which offsets modal gain factors of the modal constituency to favor a preferred set of modes supporting efficient radial emission out of the total modal constituency supported by the resonator. Under appropriate pump actuation the selected modes produce circumferential laser radiation with the output surface comprising of the entire outer perimeter of the cylindrical ring waveguide. The design is applicable toward both micro-resonators and resonators much larger than the optical wavelength, enabling high output powers and scalability. The circumferential radial laser emission can be concentrated by positioning the cylindrical ring laser inside a three-dimensional conical mirror thereby forming a laser ring of light propagating in the axial dimension away from the surface of the laser, which can be subsequently collimated for focused using conventional optics.

A laser includes an active region surrounded by first and second waveguide layers. Two or more mask openings are formed within a dielectric layer on a surface parallel to the active region. A refractive grating is formed on the dielectric mask openings and includes three-dimensional grating features spaced apart in the light-propagation direction of the laser. The refractive grating provides modulation of a real part of the effective refractive index of the laser and modulation of the imaginary part is provided by modulation of the current flow through the mask openings.

A semiconductor laser diode includes a semiconductor layer sequence with an active layer having a main extension plane and that generates light in an active region and emits light via a light outcoupling surface during operation, wherein the active region extends from a rear surface opposite the light outcoupling surface to the light outcoupling surface along a longitudinal direction, the semiconductor layer sequence includes a trench structure having at least one trench or a plurality of trenches on at least one side laterally next to the active region, and each trench of the trench structure extends in a longitudinal direction and projects from a top side of the semiconductor layer sequence in a vertical direction into the semiconductor layer sequence, and the trench structure varies in a lateral and/or vertical and/or longitudinal direction with respect to properties of the at least one trench or the plurality of trenches.

Optical gain media and gain devices are required for lasing devices and high intensity optical systems across a wide range of application. A compact optical gain device that provides near-infrared and infrared lasing at room temperature includes an optical microcavity having a refractive index and a curvilinear outer surface with an angle of curvature such that the optical microcavity supports the propagation of an electromagnetic whispering gallery mode. A plurality of optical gain structures are disposed along the curvilinear outer surface of the optical microcavity, the each of the optical gain structures having an optically active wavelength range over which each of the corresponding optical gain structures provides optical gain to radiation through stimulated emission.

A two-dimensional photonic crystal surface emitting laser has, in a plate-shaped base body, a two-dimensional photonic crystal layer in which modified refractive index region pairs are periodically arranged and an active layer provided on one side of the base body, each of the modified refractive index region pairs including a first modified refractive index region and a second modified refractive index region having refractive indexes different from a refractive index of the base body, wherein an area of a planar shape of the first modified refractive index region is larger than or equal to an area of a planar shape of the second modified refractive index region, and a thickness of the first modified refractive index region is smaller than a thickness of the second modified refractive index region.

A two-dimensional photonic crystal surface emitting laser has, in a plate-shaped base body, a two-dimensional photonic crystal layer in which modified refractive index region pairs are periodically arranged and an active layer provided on one side of the base body, each of the modified refractive index region pairs including a first modified refractive index region and a second modified refractive index region having refractive indexes different from a refractive index of the base body, wherein an area of a planar shape of the first modified refractive index region is larger than or equal to an area of a planar shape of the second modified refractive index region, and a thickness of the first modified refractive index region is smaller than a thickness of the second modified refractive index region.

A semiconductor laser includes a main body, a strip having a narrower width provided on the main body, and an active zone that generates light radiation, wherein surfaces of the main body laterally with respect to the strip and side surfaces of the strip are covered with an electrically insulating protective layer, an electrically conductive layer as a contact is provided on a top side of the strip, a cavity is provided between a side surface of the strip and the protective layer at least in a delimited section.

A quantum dot laser includes a GaAs substrate, a quantum dot active layer which has a barrier layer of GaAs and quantum dots, a GaAs waveguide core layer which is joined to the quantum dot active layer, and a lower cladding layer and an upper cladding layer which sandwich the quantum dot active layer and the GaAs waveguide core layer. The GaAs waveguide core layer extends from a front end of the quantum dot active layer and has a thickness which gradually decreases in a direction to depart from the front end of the quantum dot active layer, a refractive index of a first cladding layer is higher than a refractive index of a second cladding layer. With this structure, expansion of the optical mode diameter that is more than necessary is inhibited to prevent leakage of light, thereby obtaining sufficient optical output.