A laser diode chip has a laser facet, which includes a coating. The coating includes an inorganic layer and an organic layer. In one example, the coating has a number of inorganic layers, including a heat-conductive layer. For example, the inorganic layers may form a reflection-increasing or reflection-decreasing layer sequence.

A circuit (e.g., for use in a time-of-flight camera projector module) may include a top metal layer having an anode and a cathode, one or more capacitors connected to the anode, a vertical-cavity surface-emitting laser connected to the anode and the cathode, and a driver connected to the cathode. The circuit may further include a bottom metal layer connected to ground and arranged below the top metal layer, and a dielectric layer separating the top metal layer and the bottom metal layer. In some implementations, the dielectric layer has a thickness under sixty micrometers and a thermal resistance under fifteen degrees Celsius per watt. Accordingly, a current loop flowing vertically across the dielectric layer has a low self-inductance based on the thickness of the dielectric layer and the bottom metal layer is arranged to dissipate heat generated by the current loop flowing vertically across the dielectric layer.

The invention relates to a semiconductor laser comprising a semiconductor layer arrangement, having an active zone for radiation generation, as well as comprising a first resonator mirror, a second resonator mirror and a resonator arranged between the first and the second resonator mirror, which ends in a direction parallel to a main surface of the semiconductor layer arrangement. The semiconductor laser also comprises a first wavelength-selective absorption element which is arranged between the semiconductor layer arrangement and the first resonator mirror.

According to embodiments, a semiconductor laser comprises a semiconductor layer stack, which comprises an active zone for generating radiation. The semiconductor laser also comprises a first resonator mirror, a second resonator mirror, and an optical resonator, which is arranged between the first and second resonator mirrors and extends in a direction parallel to a main surface of the semiconductor layer stack. A reflectance R1 of the first resonator mirror is wavelength-dependent, so that R1 or a product R of R1 and the reflectance R2 of the second resonator mirror in a wavelength range decreases from a target wavelength λ.sub.0 of the laser to λ.sub.0+Δλ from a value R0, wherein Δλ is selected as a function of a temperature-dependent shift in an emission wavelength.

A nitride semiconductor laser element includes a nitride semiconductor stack body and a protective film. The nitride semiconductor stack body includes first and second nitride semiconductor layers and an active layer disposed between the first nitride semiconductor layer and the second nitride semiconductor layer. The nitride semiconductor stack body defines a light-emission-side end face intersecting a face of the active layer on a second nitride semiconductor layer side, and a light-reflection-side end face intersecting the face of the active layer on the second nitride semiconductor layer side. The protective film is disposed on the light-emission-side end face of the nitride semiconductor stack body. The protective film includes, in the order from the light-emission-side end face, a first film that is a crystalline film containing oxygen and aluminum and/or gallium, a second film that is a nitride crystalline film, and a third film containing aluminum and oxygen.

A light emitting device is provided that makes it possible to reduce absorption of light by an electrode. The light emitting device includes a substrate, and a laminated structure provided to the substrate, wherein the laminated structure includes a first semiconductor layer, a second semiconductor layer different in conductivity type from the first semiconductor layer, and an active layer disposed between the first semiconductor layer and the second semiconductor layer, the first semiconductor layer is disposed between the substrate and the active layer, a recessed part is disposed at an opposite side to the substrate side of the laminated structure, the recessed part is provided with a low refractive-index part lower in refractive index than the second semiconductor layer, a depth of the recessed part is no larger than a distance between a surface at an opposite side to the substrate side of the laminated structure and the active layer, and an electrode is disposed at an opposite side to the substrate side of the laminated structure.

Methods of passivating at least one facet of a multilayer waveguide structure can include: cleaning, in a first chamber of a multi-chamber ultra-high vacuum (UHV) system, a first facet of the multilayer waveguide structure; transferring the cleaned multilayer waveguide structure from the first chamber to a second chamber of the multi-chamber UHV system; forming, in the second chamber, a first single crystalline passivation layer on the first facet; transferring the multilayer waveguide structure from the second chamber to a third chamber of the multi-chamber UHV system; and forming, in the third chamber, a first dielectric coating on the first single crystalline passivation layer, in which the methods are performed in an UHV environment of the multi-chamber UHV system without removing the multilayer waveguide structure from the UHV environment.

A very strong selection mechanism is provided in a tunable vertical cavity surface emitting laser (VCSEL) by manipulating the laser threshold to be different for TE and TM polarization by a employing a subwavelength grating in the laser cavity. The laser selects the polarization with the lowest threshold. The grating does not diffract and does not add loss to the cavity. It works by creating a large birefringence layer between the semiconductor and air sub-cavities of the full VCSEL. Multilayer stack calculations show that this results in a lower threshold for the TM polarization over the TE. This subwavelength grating layer, in one embodiment, replaces the AR coating on the semiconductor surface.

A light emitting element comprising a layered structure configured by layering a first light reflecting layer 41 configured by layering a plurality of thin films, a light emitting structure 20, and a second light reflecting layer 42 configured by layering a plurality of thin films, wherein the light emitting structure 20 is configured by layering, from the first light reflecting layer side, a first compound semiconductor layer 21, an active layer 23, and a second compound semiconductor layer 22, a second electrode 32 and an intermediate layer 70 are formed between the second compound semiconductor layer 22 and the second light reflecting layer 42 from the second compound semiconductor layer side, and the value of a surface roughness of a second surface 72 of the intermediate layer 70 in contact with the second light reflecting layer 42 is less than the value of a surface roughness of a first surface 71 of the intermediate layer 70 facing the second electrode 32.

A laser element comprises a substrate, an adhesive layer, and a laser unit adhesive to the substrate by the adhesive layer. The laser unit includes a front conductive structure, a first type semiconductor stack, an active layer, a second type semiconductor stack, a patterned insulating layer, a back conductive structure. The back conductive structure includes a first electrode and a second electrode, and the first electrode of the back conductive structure contacts the second type semiconductor stack. A via hole passing through the patterned insulating layer, the second type semiconductor stack, the active layer and the first type semiconductor stack, and a conductive channel located in the via hole and electrically connected to the second electrode of the back conductive structure and the front conductive structure. A first passivation layer formed on a sidewall of the via hole and located between the conductive channel and the sidewall of the via hole.