A semiconductor laser comprises a window structure part including a low resistance active layer formed in end face regions, to have a lower resistance than an active layer located inward with respect to the end face regions. A length between the front end of the contact layer and the front end face is longer by 10 μm or more than a length of a front-end-face side window structure part, and is shorter than a length between the front end face and the rear end of the contact layer. A length between an end of a rear side electrode on the side of the front end face and the front end face is 1.2 times or more a substrate thickness of a substrate, and is shorter than a length between the front end face and an end of the rear side electrode on the side of the rear end face.

The present technology can be used to control the current injection profile in the longitudinal direction of a high-power diode laser in order to optimize current densities as a function of position in the cavity to promote higher reliable output power and increase the electrical to optical conversion efficiency of the device beyond the level which can be achieved without application of this technique. This approach can be utilized, e.g., in the fabrication of semiconductor laser chips to improve the output power and wall plug efficiency for applications requiring improved performance operation.

A semiconductor laser includes an active layer which emits laser light and cladding layers being formed so as to sandwich the active layer. The active layer includes a quantum dot layer including a plurality of quantum dots, which respectively confine movements of carriers in the three-dimensional directions. The laser radar device includes a light projection part which projects laser light and a light receiving part which receives reflected light of the laser light. The light projection part includes the semiconductor laser and a scanner which reflects the laser light, emitted from the semiconductor laser, to form a scanning laser light.

A semiconductor laser element that includes a semiconductor layer including a waveguide formed in an intra-layer direction of the semiconductor layer and a window region formed in a front-side end face of the waveguide, has a current-laser optical output characteristic in which, at an operating temperature of 25° C.±3° C., a laser optical output has a maximum value at a first driving current value and the laser optical output is at most 20% of the maximum value at a second driving current value greater than the first driving current value, and is not damaged at the second driving current value.

A semiconductor laser device lases in a multiple transverse mode and includes a stacked structure where a first conductivity-side semiconductor layer, an active layer, and a second conductivity-side semiconductor layer are stacked above a substrate. The second conductivity-side semiconductor layer includes a current block layer having an opening that delimits a current injection region. Side faces as a pair are formed in portions of the stacked structure that range from part of the first conductivity-side semiconductor layer to the second conductivity-side semiconductor layer. The active layer has a second width greater than a first width of the opening. The side faces in at least part of the first conductivity-side semiconductor layer are inclined to the substrate. A maximum intensity position in a light distribution of light guided in the stacked structure, in a direction of the normal to the substrate, is within the first conductivity-side semiconductor layer.

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 laser chip including a plurality of stripes is disclosed, where a laser stripe can be grown with an initial optical gain profile, and its optical gain profile can be shifted by using an intermixing process. In this manner, multiple laser stripes can be formed on the same laser chip from the same epitaxial wafer, where at least one laser stripe can have an optical gain profile shifted relative to another laser stripe. For example, each laser stripe can have a shifted optical gain profile relative to its neighboring laser stripe, thereby each laser stripe can emit light with a different range of wavelengths. The laser chip can emit light across a wide range of wavelengths. Examples of the disclosure further includes different regions of a given laser stripe having different intermixing amounts.

An on-chip integrated semiconductor laser structure and a method for preparing the same. The structure includes: an epitaxial structure including a first N contact layer, a first N confinement layer, a first active region, a first P confinement layer, a first P contact layer, an isolation layer, a second N contact layer, a second N confinement layer, a second active region, a second P confinement layer, and a second P contact layer sequentially deposited on a substrate; a first waveguide and a second waveguide; a first optical grating and a second optical grating; and current injection windows.

An on-chip integrated semiconductor laser structure and a method for preparing the same. The structure includes: an epitaxial structure including a first N contact layer, a first N confinement layer, a first active region, a first P confinement layer, a first P contact layer, an isolation layer, a second N contact layer, a second N confinement layer, a second active region, a second P confinement layer, and a second P contact layer sequentially deposited on a substrate; a first waveguide and a second waveguide; a first optical grating and a second optical grating; and current injection windows.

A multi-section laser device is configured with a gain section and an integrated photodetector section. The photodetector section, rather than being a separate component, is integrated directly into the body of the laser. The integrated photodetector section absorbs photons generated by the gain section and creates a photocurrent that is proportional to the output of the multi-section laser device. The measured photocurrent is usable to calculate power output of the multi-section laser device and to identify any adjustments that may be needed to be made to the laser in order to achieve desired laser light output.