A electro-absorption optical modulator includes a multiple quantum well composed of a plurality of layers including a plurality of quantum well layers and a plurality of barrier layers that are alternately stacked, the plurality of quantum well layers and the plurality of barrier layers including an acceptor and a donor; a p-type semiconductor layer in contact with an uppermost layer of the plurality of layers; and an n-type semiconductor layer in contact with a lowermost layer of the plurality of layers, the multiple quantum well being 10% or more and 150% or less of the p-type semiconductor layer in a p-type carrier concentration, and in the multiple quantum well, an effective carrier concentration which corresponds to a difference between the p-type carrier concentration and an n-type carrier concentration is 10% or less of the p-type carrier concentration of the multiple quantum well.

A semiconductor optical element is configured to emit or absorb light and includes a lower structure that includes a multiple quantum well layer; an upper mesa structure that is disposed on the lower structure; a current injection structure that is disposed on the upper mesa structure, when seen from an optical axis of the emitted or absorbed light, a width of a portion of the current injection structure in contact with the upper mesa structure is smaller than a width of the upper mesa structure, the portion of the current injection structure in contact with the upper mesa structure consisting of InP, and an average refractive index of the upper mesa structure is higher than a refractive index of the InP forming the current injection structure; and an insulating film covering both side surfaces of the upper mesa structure and a part of an upper surface of the upper mesa structure.

In general, a MQW semiconductor laser chip with an electrically insulated P-side region and a process for forming the same is disclosed. The MQW semiconductor laser chip, also referred to herein as a MQW semiconductor laser or simply a semiconductor laser, includes a layer of electrically insulative material that extends along at least a portion of the sidewalls to minimize or otherwise reduce the potential for electrical shorts between P and N-sides of the same when utilizing P-side bonding techniques.

A semiconductor light emitting device includes a substrate, and an array including three or more light emitting elements which are aligned above and along a main surface of a substrate and each emit light. The light emitting elements each include a clad layer of a first conductivity type, an active layer containing In, and a clad layer of a second conductivity type disposed above the substrate sequentially from the substrate. Among the light emitting elements, the compositional ratio of In in the active layer is smaller in the light emitting element located in a central area in an alignment direction than that in the light emitting elements located in both end areas in the alignment direction.

According to an embodiment, a wavelength tunable laser comprising a gain region and a wavelength tunable area is disclosed. The wavelength tunable area comprises: a lower clad layer; a passive optical waveguide positioned on the lower clad layer; an upper clad layer positioned on the passive optical waveguide; a drive electrode positioned on the upper clad layer; a current blocking layer positioned on the drive electrode; a heater positioned on the current blocking layer; and a first insulating groove and a second insulating groove which are positioned so as to face each other with the passive optical waveguide therebetween.

A light emission device of one embodiment reduces zero-order light included in output of an S-iPM laser. The light emission device includes a light emission unit and a phase modulation layer. The phase modulation layer has a base layer and modified refractive index regions each including modified refractive index elements. In each unit constituent region centered on a lattice point of an imaginary square lattice set on the phase modulation layer, the distance from the corresponding lattice point to each of the centers of gravity of the modified refractive index elements is greater than 0.30 times and is not greater than 0.50 times of the lattice spacing. In addition, the distance from the corresponding lattice point to the center of gravity of the modified refractive index elements as a whole is greater than 0 and is not greater than 0.30 times of the lattice spacing.

In one embodiment of the invention, the semiconductor laser (1) comprises a semiconductor layer sequence (2). The semiconductor layer sequence (2) contains an n-type region (23), a p-type region (21) and an active zone (22) lying between the two. A laser beam is produced in a resonator path (3). The resonator path (3) is aligned parallel to the active zone (22). In addition, the semiconductor laser (1) contains an electrical p-contact (41) and an electrical n-contact (43) each of which is located on the associated region (21, 23) of the semiconductor layer sequence (2) and is configured to input current directly into the associated region (21, 23). A p-contact surface (61) is electrically connected to the p-contact (41), and an n-contact surface (63) is electrically connected to the n-contact (43) such that the p-contact surface (61) and the n-contact surface (63) are configured for external electrical and mechanical connection of the semiconductor laser (1). The contact surfaces (61, 63) are oriented parallel to a growth direction (G) of the semiconductor layer sequence (2). The semiconductor laser (1) can be surface-mounted without wires.

The present disclosure describes broadband optical emission sources that include a stack of semiconductor layers, wherein each of the semiconductor layers is operable to emit light of a different respective wavelength; a light source operable to provide optical pumping for stimulated photon emission from the stack; wherein the semiconductor layers are disposed sequentially in the stack such that a first one of the semiconductor layers is closest to the light source and a last one of the semiconductor layers is furthest from the light source, and wherein each particular one of the semiconductor layers is at least partially transparent to the light generated by the other semiconductor layers that are closer to the light source than the particular semiconductor layer. The disclosure also describes various spectrometers that include a broadband optical emission device, and optionally include a tuneable wavelength filter operable to allow a selected pass through.

A semiconductor laser element that includes a stripe-shaped light-emitting region and that is formed by adhering a surface of the semiconductor laser element on a side opposite to a semiconductor substrate and a submount to each other by a solder layer includes a terrace section on a surface of the semiconductor laser element that is adhered by the solder layer, the terrace section being separated from a ridge portion, which is a current-carrying portion, by a grooved portion. A top surface of a region including the grooved portion is covered by a metal. The terrace section is divided into a plurality of portions that are disposed in a scattered manner.

A semiconductor laser element includes: a substrate; and a laser array portion that includes a plurality of light emitting portions arranged side by side, and is stacked above the substrate, wherein a stacked body of the substrate and the laser array portion includes a pair of resonator end faces on opposite faces, and a groove portion that extends from the laser array portion into the substrate is provided on at least one of the pair of resonator end faces between two adjacent light emitting portions among the plurality of light emitting portions.