A semiconductor laser device includes a semiconductor substrate, a resonator unit formed on the semiconductor substrate and having an active layer, a diffraction grating formed on or underneath the active layer, a front facet of an inverted mesa slope, and a rear facet, an anti-reflection coating film formed on the front facet, a reflective film formed on the rear facet, an upper electrode formed on the resonator unit, and a lower electrode formed underneath the semiconductor substrate, wherein a length in a resonator direction of the resonator unit is shorter than a length in the resonator direction of the semiconductor substrate, and a laser beam is emitted from the front facet.

Edge-emitting laser diodes having mirror facets include passivation coatings that are conditioned using an ex-situ process to condition the insulating material used to form the passivation layer. An external energy source (laser, flash lamp, e-beam) is utilized to irradiate the material at a given dosage and for a period of time sufficient to condition the complete thickness of passivation layer. This ex-situ laser treatment is applied to the layers covering both facets of the laser diode (which may comprise both the passivation layers and the coating layers) to stabilize the entire facet overlay. Importantly, the ex-situ process can be performed while the devices are still in bar form.

A semiconductor optical amplifier includes: a substrate; a light source unit formed on the substrate; and an optical amplification part that amplifies light propagating in a predetermined direction from the light source unit and emits the amplified light in an emission direction intersecting with the substrate surface. The optical amplification part includes a conductive region extending in the predetermined direction along the substrate surface from the light source unit, and a nonconductive region formed around the conductive region. The conductive region includes a first region extending from the light source unit and having a predetermined width as seen from a direction perpendicular to the substrate surface, and a second region connected to the first region and having a width widened relative to the predetermined width of the first region, the second region being configured to expand the propagation light in a direction intersecting with the predetermined direction.

A front facet of the semiconductor laser device includes a resonator facet portion containing an end of an active layer, and a protruding portion which protrudes beyond the resonator facet portion in a resonator length direction by a predetermined protrusion amount and has a stepped bottom surface portion. The resonator facet portion and the stepped bottom surface portion are connected to each other to form a corner portion. The distance from a thickness center position of the active layer to the stepped bottom surface portion is defined by a bottom surface portion depth. The bottom surface portion depth is set to be equal to a predetermined specific depth or deeper than the specific depth.

In a semiconductor laser device, a semiconductor layer includes a first groove formed on both sides of a ridge, a pair of second recesses facing each other and between which the ridge is interposed on a side of a light emitting surface, and a pair of third grooves in parallel to the first groove from the light emitting surface and interposing the ridge therebetween.

A laser diode includes a semiconductor body having a substrate and a semiconductor layer sequence arranged on the substrate, which includes an active zone that generates electromagnetic radiation, wherein the semiconductor body has a first main surface and a second main surface opposite the first main surface and at least one first and second laser facet, which are respectively arranged transversely to the first and second main surfaces, and at least one structured facet region located at a transition between the first main surface and at least one of the first and second laser facets, and the structured facet region includes at least a strained compensation layer or a recess.

Edge-emitting laser diodes having mirror facets include passivation coatings that are conditioned using an ex-situ process to condition the insulating material used to form the passivation layer. An external energy source (laser, flash lamp, e-beam) is utilized to irradiate the material at a given dosage and for a period of time sufficient to condition the complete thickness of passivation layer. This ex-situ laser treatment is applied to the layers covering both facets of the laser diode (which may comprise both the passivation layers and the coating layers) to stabilize the entire facet overlay. Importantly, the ex-situ process can be performed while the devices are still in bar form.

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 quantum dot comb laser includes a body defining a lasing cavity and an extension defining an external cavity, the FSR of the lasing cavity being an inverse of an integer multiple of the FSR of the external cavity.

A folded lasing cavity comprises at least one bend. The folded lasing cavity is disposed on and configured to emit light along a substrate-parallel plane. An etched facet is on an emitting end of the folded lasing cavity and an etched mirror is on another end of the folding lasing cavity. An etched shaping mirror redirects light received from the etched facet in a direction normal to the substrate-parallel plane.