The disclosed technology relates to the development of a monolithic active electro-optical device. The electro-optical device may be fabricated using the so-called nanoridge aspect ratio trapping (ART) approach. In one aspect, the disclosed technology is directed to a monolithic integrated electro-optical device, which comprises a III-V-semiconductor-material ridge structure arranged on a Si-based support region. The ridge structure includes a first-conductivity-type bottom region arranged on the support region, a first-conductivity-type lower blocking layer arranged on the top surface and parts of the side surfaces of the bottom region and configured to block second-conductivity-type charge carriers, a not-intentionally-doped (NID) intermediate region arranged on the top and side surfaces of the lower blocking layer and containing a recombination region, a second-conductivity-type upper blocking layer arranged on the top and side surfaces of the intermediate region and configured to block first-conductivity-type charge carriers, and a second-conductivity-type top region arranged on the top and side surfaces of the upper blocking layer.

A laser or light emitter for operation at a cryogenic temperature includes a single quantum well layer, an n-type barrier layer directly on a first surface of the single quantum well layer, and a p-type barrier layer directly on a second surface of the single quantum well layer opposite the first surface of the single quantum well layer. The single quantum well layer is between the p-type barrier layer and the n-type barrier layer and the compositions of the n-type barrier layer and the p-type barrier layer are graded.

A semiconductor light emitting element has a laminated structure formed by laminating a first compound semiconductor layer, an active layer, and a second compound semiconductor layer. The semiconductor light emitting element satisfies I.sub.2>I.sub.1, where I.sub.1 is an operating current range when the temperature of the active layer is T.sub.1, and I.sub.2 is the operating current range when the temperature of the active layer is T.sub.2 (where T.sub.2>T.sub.1). The semiconductor light emitting element satisfies P.sub.2>P.sub.1, where P.sub.1 is a maximum optical output emitted when the temperature of the active layer is T.sub.1, and P.sub.2 is the maximum optical output emitted when the temperature of the active layer is T.sub.2 (where T.sub.2>T.sub.1).

A monolithic laser device assembly 10A in the present disclosure includes a first gain portion 20 having a first end portion 20A and a second end portion 20B, a second gain portion 30 having a third end portion 30A and a fourth end portion 30B, one or multiple ring resonators 40, a semiconductor optical amplifier 50 for amplifying a laser light emitted from the first gain portion 20, and a pulse selector 60 disposed between the first gain portion 20 and the semiconductor optical amplifier 50, in which the ring resonator 40 is optically coupled with the first gain portion 20 and with the second gain portion 30, and laser oscillation is performed on either the first gain portion 20 or the second gain portion 30.

A Dual-wavelength hybrid (DWH) device includes an n-type ohmic contact layer, cathode and anode terminal electrodes, first and second injector terminal electrodes, p-type and n-type modulation doped QW structures, and first through sixth ion implant regions. The first injector terminal electrode is formed on the third ion implant region that contacts the p-type modulation doped QW structure and the second injector terminal electrode is formed on the fourth ion implant region that contacts the n-type modulation doped QW structure. The DWH device operates in at least one of a vertical cavity mode and a whispering gallery mode. In the vertical cavity mode, the DWH device converts an in-plane optical mode signal to a vertical optical mode signal, whereas in the whispering gallery mode the DWH device converts a vertical optical mode signal to an in-plane optical mode signal.

A vertical cavity surface emitting laser includes: a supporting base having a principal surface including III-V compound semiconductor containing gallium and arsenic as constituent elements; and a post disposed on the principal surface. The post has a lower spacer region including a III-V compound semiconductor containing gallium and arsenic as group-III elements, and an active layer having a quantum well structure disposed on the lower spacer region. The quantum well structure has a concentration of carbon in a range of 210.sup.16 cm.sup.3 or more to 510.sup.16 cm.sup.3 or less. The quantum well structure includes a well layer and a barrier layer. The well layer includes a III-V compound semiconductor containing indium as a group-III element, and the barrier layer includes a III-V compound semiconductor containing indium and aluminum as group-III elements. The lower spacer region is disposed between the supporting base and the active layer.

A semiconductor module of the present disclosure includes: a base body including a groove part of which two inner side surfaces are inclined, the base body including an electrode pad which is provided on at least one inner side surface; and a semiconductor element including a semiconductor substrate including a first surface, a second surface opposite to the first surface, and two side surfaces which are inclined in a diagonal direction to the first surface and are opposite to each other, a semiconductor layer located on the first surface, and an electrode disposed on at least one side surface. The semiconductor element is located in the groove part so that the at least one side surface is disposed along the at least one inner side surface of the base body, and at least one electrode of the semiconductor element is connected to the electrode pad of the base body.

A semiconductor optical amplifier for high-power operation includes a gain medium having a multilayer structure sequentially laid with a P-layer, an active layer, a N-layer from an upper portion to a lower portion in cross-section thereof. The gain medium is extendedly laid with a length L from a front facet to a back facet. The active layer includes multiple well layers formed by undoped semiconductor material and multiple barrier layers formed by n-doped semiconductor materials. Each well layer is sandwiched by a pair of barrier layers. The front facet is characterized by a first reflectance Rf and the back facet is characterized by a second reflectance Rb. The gain medium has a mirror loss .sub.m about 40-200 cm.sup.1 given by: .sub.m=(L)ln{1/(RfRb)}.

A semiconductor module of the present disclosure includes: a base body including a groove part of which two inner side surfaces are inclined, the base body including an electrode pad which is provided on at least one inner side surface; and a semiconductor element including a semiconductor substrate including a first surface, a second surface opposite to the first surface, and two side surfaces which are inclined in a diagonal direction to the first surface and are opposite to each other, a semiconductor layer located on the first surface, and an electrode disposed on at least one side surface. The semiconductor element is located in the groove part so that the at least one side surface is disposed along the at least one inner side surface of the base body, and at least one electrode of the semiconductor element is connected to the electrode pad of the base body.

Surface-emitting laser devices and light-emitting devices including the same are provided. A surface-emitting laser device can include: a first reflective layer and a second reflective layer; and an active region disposed between the first reflective layer and the second reflective layer, wherein the first reflective layer includes a first group first reflective layer and a second group first reflective layer, and the second reflective layer includes a first group second reflective layer and a second group second reflective layer.