A Bragg grating includes a lower waveguide layer, a middle waveguide layer disposed on the lower waveguide layer, an upper waveguide structure disposed on the middle waveguide layer opposite to the lower waveguide layer, and a buried layer. The upper waveguide structure includes upper waveguide elements that are arranged on a surface of the middle waveguide layer, and that are spaced apart from one another by cavities. The buried layer fills the cavity. The middle waveguide layer has a refractive index lower than that of each of the lower waveguide layer and the upper waveguide elements. The lower waveguide layer has a doping type the same as that of the middle waveguide layer. A method for manufacturing the Bragg grating is also provided.

The invention relates to a method for fabricating a semiconductor structure. The method comprises fabricating a photonic crystal structure of a first material, in particular a first semiconductor material and selectively removing the first material within a predefined part of the photonic crystal structure. The method further comprises replacing the first material within the predefined part of the photonic crystal structure with one or more second materials by selective epitaxy. The one or more second materials may be in particular semiconductor materials. The invention further relates to devices obtainable by such a method.

A non-etched gap is introduced along the length of an integrated Bragg grating with etched grooves such that the coupling coefficient, K, of the grating is reduced by the non-etched gap. In this way, multiple grating K values may be defined within a photonic integrated circuit using a single lithography and etch step. Additionally, the non-etched gap width may be varied along the length of a single grating to implement a chirped grating.

Disclosed is a current-injection organic semiconductor laser diode comprising a pair of electrodes, an optical resonator structure, and one or more organic layers including a light amplification layer composed of an organic semiconductor, which has a sufficient overlap between the distribution of excitor density and the electric field intensity distribution of the resonant optical mode during current injection to emit laser light.

Disclosed is a current-injection organic semiconductor laser diode comprising a pair of electrodes, an optical resonator structure, and one or more organic layers including a light amplification layer composed of an organic semiconductor, which has a sufficient overlap between the distribution of exciton density and the electric field intensity distribution of the resonant optical mode during current injection to emit laser light.

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.

Disclosed is a current-injection organic semiconductor laser diode comprising a pair of electrodes, an optical resonator structure, and one or more organic layers including a light amplification layer composed of an organic semiconductor, which has a sufficient overlap between the distribution of excitor density and the electric field intensity distribution of the resonant optical mode during current injection to emit laser light.

A distributed feedback laser integrated on silicon comprising a combination of a waveguide of a first material and a laser diode a second material, different from the first material, wherein the laser diode comprises a plurality of regularly spaced metalized grating elements which form a single longitudinal mode; wherein the waveguide comprises a plurality of waveguide elements separated by metalized regions; and wherein the metalized grating elements and the metalized regions are adapted to be coupled to one another to form the distributed feedback laser.

The invention relates to laser diode for generating laser radiation of at least two frequencies, comprising: a semiconductor body having a ridge waveguide; a DFB structure or DBR structure in the ridge waveguide; and a piezoelectric element for producing mechanical stress in the ridge waveguide, which piezoelectric element is arranged on the ridge waveguide. The invention further relates to a method for producing laser radiation of at least two frequencies by means of the laser diode.

Disclosed is an electrically driven organic semiconductor laser diode comprising a pair of electrodes, an optical resonator structure having a distributed feedback (DFB) structure, and one or more organic layers including a light amplification layer composed of an organic semiconductor, in which the distributed feedback structure is composed of a first-order Bragg scattering region, a two-dimensional distributed feedback, or a circular distributed feedback.