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.

The invention relates to a laser diode (10) which has at least one active layer (12) which is arranged within a resonator (14) and is operatively connected to a outcoupling element (16), and further at least one contact layer (18) for coupling charge carriers into the active layer (12), wherein the resonator (14) comprises at least a first section (20) and a second section (22), wherein the second section (22) comprises a plurality of separate resistor elements (24) having a specific electrical resistivity greater than the specific electrical resistivity of the regions (26) between adjacent resistor elements (24), wherein a width (W3) of the resistor elements (24) along a longitudinal axis (X1) of the active layer (12) is less than 20 m, and a projection of the resistor elements (24) on the active layer (12) along the first axis (Z1) overlap with at least 10% of the active layer (12).

A semiconductor laser device is provided with a semiconductor layer including an active layer and a plurality of cladding layers sandwiching the active layer. The active layer includes a stripe-shaped active region, a pair of first refractive index regions and a pair of second refractive index regions sandwiching the active layer and the pair of first refractive index regions. When ? is the laser oscillation wavelength, n.sub.a is the effective refractive index of the active region, n.sub.c is the effective refractive index of the first refractive index regions, n.sub.t is the effective refractive index of the second refractive index regions, w is the width of the active region, and m is a positive integer, the semiconductor laser device satisfies n.sub.a>n.sub.t>n.sub.c, and the conditions of equations (5), (8) and (9).

A semiconductor chip (100) is provided, having a first semiconductor layer (1), which has a lateral variation of a material composition along at least one direction of extent. Additionally provided is a method for producing a semiconductor chip (100).

A semiconductor laser diode includes a layer sequence including a plurality of layers arranged one above another in a growth direction, wherein the semiconductor laser diode includes a first facet and a second facet between which a resonator extending in a longitudinal direction is formed, the layer sequence includes an active layer in which an active region is formed, the layer sequence includes waveguide layers, and the layer sequence includes a stressed layer arranged above the active layer in the growth direction, the stressed layer being provided for influencing a refractive index profile in the waveguide layers at least to partly compensate for an inhomogeneous variation of a refractive index in the waveguide layers, the inhomogeneous variation being brought about by an inhomogeneous temperature distribution during operation of the semiconductor laser diode.

A QCL may include a substrate, an emitting facet, and semiconductor layers adjacent the substrate and defining an active region. The active region may have a longitudinal axis canted at an oblique angle to the emitting facet of the substrate. The QCL may include an optical grating being adjacent the active region and configured to emit one of a CW laser output or a pulsed laser output through the emitting facet of substrate.

Methods and apparatus for spectral narrowing and wavelength stabilization of broad-area lasers, such as an apparatus including a broad-area laser source configured to emit light along an emission axis in an emission pattern extending along the emission axis, and a single-mode fiber Bragg grating, such as a single-mode core incorporating a fiber Bragg grating embedded in a core of a dual-clad fiber, the single-mode fiber Bragg grating configured to spectrally selectively reflect back light from a sub-aperture portion of the emitted light to the broad-area laser source. The single mode core having the FBG is off-axis in comparison to the central axis of the double-clad fiber and allows for frequency stabilization of the broad area laser diode output improving its performance as pump laser for a doped fiber amplifier.

A semiconductor chip (100) is provided, having a first semiconductor layer (1), which has a lateral variation of a material composition along at least one direction of extent. Additionally provided is a method for producing a semiconductor chip (100).

A QCL may include a substrate, an emitting facet, and semiconductor layers adjacent the substrate and defining an active region. The active region may have a longitudinal axis canted at an oblique angle to the emitting facet of the substrate. The QCL may include an optical grating being adjacent the active region and configured to emit one of a CW laser output or a pulsed laser output through the emitting facet of substrate.

An edge-emitting semiconductor laser and a method for operating a semiconductor laser are disclosed. The edge-emitting semiconductor laser includes an active zone within a semiconductor layer sequence and a stress layer. The active zone is configured for being energized only in a longitudinal strip perpendicular to a growth direction of the semiconductor layer sequence. The semiconductor layer sequence has a constant thickness throughout in the region of the longitudinal strip so that the semiconductor laser is gain-guided. The stress layer may locally stress the semiconductor layer sequence in a direction perpendicular to the longitudinal strip and in a direction perpendicular to the growth direction. A refractive index of the semiconductor layer sequence, in regions which, seen in plan view, are located next to the longitudinal strip, for the laser radiation generated during operation is reduced by at least 210.sup.4 and by at most 510.sup.3.