A semiconductor laser may include an active region having a longitudinal axis, a rear facet end and a front facet end. The front facet end emitting an output beam of the semiconductor laser. The semiconductor laser may include a plurality of diffraction gratings positioned along the longitudinal axis of the active region. The plurality of diffraction gratings including a first diffraction grating positioned proximate the rear facet end of the active region and at least one additional diffraction grating positioned longitudinally between the first diffraction grating and the front facet. The first diffraction grating having a first kappa value and the at least one additional diffraction grating having at least a second kappa value, the first kappa value being greater than the second kappa value.

A laser device with one or more active regions, such as quantum wells, gain/lighting media, or other devices, and one or more non-absorbing regions, may be formed by a first growth run (growing a first semiconductor layer), then performing selective, shallow-depth etching, and then a second growth run (growing a second semiconductor layer). The laser device may include a first portion, one or more active regions located on the first portion, and a second portion located on the active region(s). A third portion may be located on one or more ends of the first portion and on the second portion. The third portion may be formed during the second growth run, after the etching step. The non-absorbing region(s) may be formed by the third portion and the end(s) of the first portion. If desired, the non-absorbing region(s) may be produced without annealing or locally-induced quantum well intermixing.

A semiconductor laser comprises: a substrate; a first cladding layer disposed above the substrate; a second cladding layer disposed above the first cladding layer so that the first cladding layer is positioned between the substrate and the second cladding layer; and a first mode expansion layer within the first cladding layer, a second mode expansion layer within the second cladding layer, or both the first mode expansion layer within the first cladding layer and the second mode expansion layer within the second cladding.

A packaged integrated white light source configured for illumination and communication or sensing comprises one or more laser diode devices. An output facet configured on the laser diode device outputs a laser beam of first electromagnetic radiation with a first peak wavelength. The first wavelength from the laser diode provides at least a first carrier channel for a data or sensing signal.

A semiconductor optical amplifier for high-power operation includes a gain medium having a multilayer structure sequentially laid with a P-layer, an active layer, a N-layer from an upper portion to a lower portion in cross-section thereof. The gain medium is extendedly laid with a length L from a front facet to a back facet. The active layer includes multiple well layers formed by undoped semiconductor material and multiple barrier layers formed by n-doped semiconductor materials. Each well layer is sandwiched by a pair of barrier layers. The front facet is characterized by a first reflectance Rf and the back facet is characterized by a second reflectance Rb. The gain medium has a mirror loss α.sub.m about 40-200 cm.sup.−1 given by: α.sub.m=(½L)ln{1/(Rf×Rb)}.

The disclosure provides a nanolaser based on a depth-subwavelength graphene-dielectric hyperbolic dispersive cavity, comprising a pumping light source and the depth-subwavelength graphene-dielectric hyperbolic dispersive cavity; wherein the depth-subwavelength graphene-dielectric hyperbolic dispersive cavity is a spherical or hemispherical hyperbolic dispersive microcavity formed by alternately wrapping a dielectric core with graphene layers and dielectric layers. Because the graphene plasmon has unique excellent performances, such as an electrical adjustability, a low intrinsic loss, a high optical field localization, and a continuously adjustable resonance frequency from mid-infrared to terahertz, compared with a common metal-dielectric hyperbolic dispersive characteristic, a graphene-dielectric hyperbolic dispersive metamaterial used by the disclosure not only may highly localize an energy of an electromagnetic wave in a more depth-subwavelength cavity, but also may reduce an ohmic loss and improve a quality factor.

A laser includes a substrate, first and second claddings, a gain medium, and multiple supports. The first cladding is spaced apart from the substrate by an air gap. A thickness of the first cladding in a vertical direction is in a range from 0.05-0.15 micrometers. The gain medium is disposed on the first cladding opposite the air gap. The second cladding is disposed on the gain medium opposite the first cladding. A thickness of the second cladding in the vertical direction is in a range from 0.05-0.15 micrometers. The supports are coupled to each of the substrate, the first cladding, the gain medium, and the second cladding to retain the first cladding, the gain medium, and the second cladding spaced apart from the substrate.

A laser diode, comprising a transverse waveguide comprising an active layer between an n-type semiconductor layer and a p-type semiconductor layer wherein the transverse waveguide is bounded by a lower index n-cladding layer on an n-side of the transverse waveguide and a lower index p-cladding layer on a p-side of the transverse waveguide a cavity that is orthogonal to the transverse waveguide, wherein the cavity is bounded in a longitudinal direction at a first end by a high reflector (HR) facet and at a second end by a partial reflector (PR) facet, and a first contact layer electrically coupled to the waveguide and configured to vary an amount of current injected into the waveguide in the longitudinal direction so as to inject more current near the HR facet than at the PR facet.

A light source or system configured to emit visible white light and infrared emissions includes a laser diode, a wavelength converter, and an infrared emitting laser diode.

A light source system or apparatus configured with an infrared illumination source includes a gallium and nitrogen containing laser diode based white light source. The light source system includes a first pathway configured to direct directional electromagnetic radiation from the gallium and nitrogen containing laser diode to a first wavelength converter and to output a white light emission. In some embodiments infrared emitting laser diodes are included to generate the infrared illumination. In some embodiments infrared emitting wavelength converter members are included to generate the infrared illumination. In some embodiments a second wavelength converter is optically excited by a UV or blue emitting gallium and nitrogen containing laser diode, a laser diode operating in the long wavelength visible spectrum such as a green laser diode or a red laser diode, by a near infrared emitting laser diode, by the white light emission produced by the first wavelength converter, or by some combination thereof. A beam shaper may be configured to direct the white light emission and an infrared emission for illuminating a target of interest and transmitting a data signal. In some configurations, sensors and feedback loops are included.