Abstract: The prior art distributed feedback laser having an InGaAlAs active layer involves a problem that its laser characteristics are deteriorated at high temperature due to the high device resistance. According to the present invention, a ridge type laser is fabricated by: forming an InGaAlAs-MQW layer 104 on a n-type InP substrate 101; growing a p-type InGaAlAs-GRIN-SCH layer 105, a p-type InAlAs electron stopping layer 106 and a p-type grating layer 107 in this order on the InGaAlAs-MQW layer 104; forming a grating; and regrowing a p-type InP cladding layer 108 and a p-type InGaAs contact layer in this order. The concave depth of the grating is smaller than the thickness of the p-type grating layer 107.

Abstract: An optical transmission device suitable for a high-speed and large-capacity optical transmission system. An optoelectronic waveguiding device including an optical waveguide layer and cladding layers each having a larger band gap than that of the optical waveguide are deposited above and beneath the optical waveguide layer formed on a semiconductor substrate. The waveguide and cladding layers comprise optical waveguides each having a MQW structure in a direction of a light propagation axis of the optical waveguide layer. Among these optical waveguides, there exists first and second optical waveguides, whose layer structures may be mutually different. The optoelectronic waveguiding device maybe characterized in that an optical waveguide made of a bulk crystal exists in a connection part between the MQW structure waveguides each having a different layer structure. The specific connected optoelectronic waveguiding device elements may include semiconductor lasers, modulators and/or amplifiers.

Abstract: An optical transmission device suitable for a high-speed and large-capacity optical transmission system. An optoelectronic waveguiding device including an optical waveguide layer and cladding layers each having a larger band gap than that of the optical waveguide are deposited above and beneath the optical waveguide layer formed on a semiconductor substrate. The waveguide and cladding layers comprise optical waveguides each having a MQW structure in a direction of a light propagation axis of the optical waveguide layer. Among these optical waveguides, there exists first and second optical waveguides, whose layer structures may be mutually different. The optoelectronic waveguiding device maybe characterized in that an optical waveguide made of a bulk crystal exists in a connection part between the MQW structure waveguides each having a different layer structure. The specific connected optoelectronic waveguiding device elements may include semiconductor lasers, modulators and/or amplifiers.

Abstract: The prior art distributed feedback laser having an InGaAlAs active layer involves a problem that its laser characteristics are deteriorated at high temperature due to the high device resistance. According to the present invention, a ridge type laser is fabricated by: forming an InGaAlAs-MQW layer 104 on a n-type InP substrate 101; growing a p-type InGaAlAs-GRIN-SCH layer 105, a p-type InAlAs electron stopping layer 106 and a p-type grating layer 107 in this order on the InGaAlAs-MQW layer 104; forming a grating; and regrowing a p-type InP cladding layer 108 and a p-type InGaAs contact layer in this order. The concave depth of the grating is smaller than the thickness of the p-type grating layer 107.

Abstract: The object of disclosing the novel art consists in providing a highly reliable mesa-structured avalanche photo-diode using a novel structure capable of keeping the dark current low, and a fabrication method thereof. The avalanche photo-diode for achieving the object has an absorption layer for absorbing light to generate a carrier, a multiplication layer for multiplying the generated carrier, and a field control layer inserted between the absorption layer and the multiplication layer. Moreover, a first mesa including at least part of the multiplication layer and part of the field control layer is formed over a substrate, a second mesa including another part of the field control layer and the absorption layer is formed over the first mesa, the area of the top surface of the first mesa is greater than that of the bottom surface of the second mesa, and a semiconductor layer is formed over the part of the first mesa top surface not covered by the second mesa and the side surface of the second mesa.

Abstract: An optical transmission device particularly adapted to a high-speed and large-capacity optical transmission system with a large optical output and excellent reflection resistance includes a waveguide-type optical element for emerging light and an optical transmission path that is to be optically coupled to the waveguide-type optical element. The waveguide-type optical element includes, at least in part thereof, a light-emitting portion having a gain-coupled diffraction grating and a mode-converting region integrated with the light-emitting portion.

Abstract: An optical transmission device particularly adapted to a high-speed and large-capacity optical transmission system with a large optical output and excellent reflection resistance includes a waveguide-type optical element for emerging light and an optical transmission path that is to be optically coupled to the waveguide-type optical element. The waveguide-type optical element includes, at least in part thereof, a light-emitting portion having a gain-coupled diffraction grating and a mode-converting region integrated with the light-emitting portion.

Abstract: An optical transmission device suitable for a high-speed and large-capacity optical transmission system. An optoelectronic waveguiding device including an optical waveguide layer and cladding layers each having a larger band gap than that of the optical waveguide are deposited above and beneath the optical waveguide layer formed on a semiconductor substrate. The waveguide and cladding layers comprise optical waveguides each having a MQW structure in a direction of a light propagation axis of the optical waveguide layer. Among these optical waveguides, there exists first and second optical waveguides, whose layer structures may be mutually different. The optoelectronic waveguiding device maybe characterized in that an optical waveguide made of a bulk crystal exists in a connection part between the MQW structure waveguides each having a different layer structure. The specific connected optoelectronic waveguiding device elements may include semiconductor lasers, modulators and/or amplifiers.

Abstract: An optical transmission device particularly adapted to a high-speed and large-capacity optical transmission system with a large optical output and excellent reflection resistance includes a waveguide-type optical element for emerging light and an optical transmission path that is to be optically coupled to the waveguide-type optical element. The waveguide-type optical element includes, at least in part thereof, a light-emitting portion having a gain-coupled diffraction grating and a mode-converting region integrated with the light-emitting portion.

Abstract: The object of disclosing the novel art consists in providing a highly reliable mesa-structured avalanche photo-diode using a novel structure capable of keeping the dark current low, and a fabrication method thereof. The avalanche photo-diode for achieving the object has an absorption layer for absorbing light to generate a carrier, a multiplication layer for multiplying the generated carrier, and a field control layer inserted between the absorption layer and the multiplication layer. Moreover, a first mesa including at least part of the multiplication layer and part of the field control layer is formed over a substrate, a second mesa including another part of the field control layer and the absorption layer is formed over the first mesa, the area of the top surface of the first mesa is greater than that of the bottom surface of the second mesa, and a semiconductor layer is formed over the part of the first mesa top surface not covered by the second mesa and the side surface of the second mesa.

Abstract: A semiconductor light-emitting device containing as first and second semiconductor layers a semiconductor of Cd.sub.x Zn.sub.1-x S.sub.y Se.sub.1-y (0<x.ltoreq.1, 0.ltoreq.y.ltoreq.1) and as an active layer a semiconductor of Cd.sub.x Zn.sub.1-x S.sub.y Se.sub.1-y (0.ltoreq.x.ltoreq.1, 0.ltoreq.y.ltoreq.1) formed between the first and second semiconductor layers, if necessary sandwiching the active layer with a pair of light guiding layers, can emit a blue laser light excellent in properties and high in reliability.

Abstract: A semiconductor emitting device is provided which is capable of emitting a blue light and, which comprises a double hetero junction structure having first clad layer, an active layer and a second clad layer, successively formed on a semiconductor substrate. First and second electrodes are respectively formed on the first and second clad layers. ZnSSe thin films of low-resistivity are preferably used as the first and/or clad second layers, while a ZnSTe film can be used as the active layer.

Abstract: A semiconductor emitting device is provided which is capable of emitting a blue light. The device includes a first clad layer, an active layer and a second clad layer, successively formed on a semiconductor substrate. A nitrogen-doped p-type ZnSSe thin film of low-resistivity having a carrier concentration of not less than 1.times.10.sup.16 cm.sup.-3 and a resistivity of not more than 10 .OMEGA.-cm is used as the first clad layer or the second clad layer.

Abstract: Strained-layer superlattices are formed on a substrate by alternately and epitaxially laminating a plurality of first compound semiconductor layers each of which is composed of a II-Vi compound semiconductor and second compound semiconductor layers each of which is composed of a II-VI or III-V compound semiconductor having a smaller lattice constant than the compound semiconductor of the first compound semiconductor layer. A first conduction type impurity diffusion region is formed in at least each layer surface of the first compound semiconductor layers, and a second conduction type region is so formed as to be adjacent to the first conduction type impurity diffusion region directly or through an undoped region. Electrodes are provided on the end side surfaces of the respective regions. The thus-obtained compound semiconductor light emitting device efficiently emits light in the visible region including green to blue wavelength region.