The present disclosure relates to a diode laser having reduced beam divergence. Some implementations reduce a beam divergence in the far field by means of a deliberate modulation of the real refractive index of the diode laser. An area of the diode laser (e.g., the injection zone), may be structured with different materials having different refractive indices. In some implementations, the modulation of the refractive index makes it possible to excite a supermode, the field of which has the same phase (in-phase mode) under the contacts. Light, which propagates under the areas of a lower refractive index, obtains a phase shift of π after passing through the index-guiding trenches. Consequently, the in-phase mode is supported and the formation of the out-of-phase mode is prevented. Consequently, the laser field can, in this way, be stabilized even at high powers such that only a central beam lobe remains in the far field.

Aspects of the present disclosure describe systems, methods, and structures that advantageously amplify optical signals through the effect of optical pump signals generated by a multicore laser diode and multicore rare-earth doped optical fiber in optical communication with a 3D waveguide structure and a multicore input signal fiber providing a plurality of optical signals for amplification.

A broad area quantum cascade laser includes an optical cavity disposed between two sidewalls, the optical cavity including an active region for producing photons when a current is applied thereto, where the optical cavity is subject to a presence of at least one high order transverse optical mode due to its broad area geometry. The broad area quantum cascade laser may also include an optically lossy material disposed on at least a first portion of one or more of the two sidewalls.

A semiconductor laser diode is disclosed. In an embodiment a semiconductor laser diode includes a semiconductor layer sequence including an active layer having a main extension plane, configured to generate light in an active region during operation and configured to radiate the light via a light-outcoupling surface, wherein the active region extends from a rear surface opposite the light-outcoupling surface to the light-outcoupling surface along a longitudinal direction in the main extension plane and a continuous contact structure directly disposed on a surface of the semiconductor layer sequence, wherein the contact structure comprises in at least a first contact region a first electrical contact material in direct contact with the surface region and in at least a second contact region a second electrical contact material in direct contact with the surface region, and wherein the first and second contact regions adjoin one another.

Disclosed herein is a laser structure comprising an active region overlying a GaAs substrate. The active region includes a dilute nitride material. The laser is configured to generate light at wavelengths greater than 1300 nm. Also disclosed herein is a photodetector comprising an absorber layer overlying a GaAs substrate. The absorber layer includes a dilute nitride material. The photodetector is configured to detect light at wavelengths greater than 1300 nm. Exemplary dilute nitride materials may include, but are not limited to, GaInNAs and GaInNAsSb. Embodiments of the disclosure may include a dilute nitride-on-GaAs laser structure and a dilute nitride-on-GaAs photodetector.

An optical module includes a stepped structure that includes a plurality of steps, a plurality of laser diodes (e.g., broad area laser diodes (BALs)), a transform lens; a grating; and an output coupler (OC). At least one laser diode, of the plurality of laser diodes, is disposed on each step of the plurality of steps of the stepped structure. The transform lens is configured to receive a plurality of laser beams emitted by the plurality of laser diodes and to direct the plurality of laser beams to the grating. The grating is configured to receive and to combine the plurality of laser beams into a single laser beam, and to direct the single laser beam to the OC. The OC is configured to receive the single laser beam from the grating and to direct a portion of the of the single laser beam out of the optical module.

An optical module includes a stepped structure; a plurality of laser minibars; a plurality of FACs; a plurality of SACs; a plurality of gratings; and an OC. At least one laser minibar, of the plurality of laser minibars, is disposed on each step of the plurality of steps of the stepped structure. The plurality of laser minibars are configured to emit a plurality of laser beams. The plurality of gratings are configured to receive the plurality of laser beams via the plurality of FACs and the plurality of SACs, to combine the plurality of laser beams into a plurality of single laser beams, and to direct the plurality of single laser beams to the OC. The OC is configured to receive the plurality of single laser beams from the plurality of gratings, and to direct a portion of the plurality of single laser beams out of the optical module.

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.

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.

Disclosed are embodiments of bidirectionally emitting semiconductor (BEST) laser architectures including higher order mode suppression structures. The higher order mode suppression structures are centrally located and extend from an inner transition boundary, which may be established by confronting high reflector (HR) facets in some embodiments or a central plane defining two sides of a unitary, bidirectional optical cavity in other embodiments. Examples of the higher order mode suppression structures include narrow regions of bidirectional flared laser oscillator waveguide (FLOW) devices, which are also referred to as reduced mode diode (REM) devices; high-index regions of bidirectional higher-order mode suppressed laser (HOMSL) devices; and non- or less-etched gain-guided lateral waveguides of bidirectional low divergence semiconductor laser (LODSL) devices. The aforementioned devices may also include scattering features, distributed feedback (DFB) gratings, distributed Bragg reflection (DBR) gratings, and combination thereof that also act as supplemental higher order mode suppression structures.