Abstract: A semiconductor light emitting light concentrating device is described which has a multiple diffraction ring for collecting and concentrating the light emitted from an LED integrally formed into the electrode at the semiconductor substrate end of the light emitting device.

Abstract: A semiconductor laser device includes an n type first cladding layer and a multi quantum well active layer successively grown on an n type substrate, a p type second cladding layer having a stripe ridge narrower in the neighborhood of the laser cavity facets than within the laser disposed on the active layer, a p type buffer layer containing p type dopants in a higher concentration than in the second cladding layer and disposed on the second cladding layer except on the stripe ridge, an n type current blocking layer disposed on the buffer layer, and a p type contact layer disposed on an upper surface of the stripe ridge and the second cladding layer and the current blocking layer, the multi quantum well being disordered except directly opposite the wider portion of the stripe ridge by the diffusion of p type dopant impurities from the p type buffer layer.

Abstract: A semiconductor laser includes a groove in a GaAs first current blocking layer, which extends to an Al.sub.x Ga.sub.(1-x) As second clad layer beneath the first blocking layer. The width of the groove periodically changes along the length of the resonator. Over the regions of the first current blocking layer where the groove has a smaller width, a Al.sub.z Ga.sub.(1-z) As second current blocking grating layer is formed. An Al.sub.x Ga.sub.(1-x) As third current blocking layer is disposed on the second current blocking layer and the portions of the first current blocking layer not covered by the second current blocking layer. The variation of the width of the groove is achieved by selective etching in gaseous hydrogen chloride by irradiation with an arsenic molecular beam, or by selective dissolution in a liquid-phase solvent but not the second current blocking layer.

Abstract: A semiconductor laser includes a first cladding layer having a forward mesa with at least one end at least partially spaced from the adjacent facet of the laser. A current blocking layer buries the mesa at its sides and at least partially at the ends of the mesa so that the ends are at least partially spaced from the facets. The current blocking layer reduces current injection and surface recombination at the facets at least partially spaced from the mesa ends, thereby increasing the catastrophic optical damage level of the laser. The mesa is formed without etching or exposing the active layer so that formation of interfaces that refract light or shorten laser life-time are avoided. An increase in COD level of about 20 percent is achieved in the invention.

Abstract: A semiconductor laser device includes an active layer, a pair of different conductivity type cladding layers having a wider energy band gap than that of the active layer, sandwiching the active layer. One of the cladding layers has a stripe ridge or stripe groove. A high dopant concentration diffusion region having the same conductivity type as that of the cladding layer is disposed on the stripe ridge or the stripe groove. Therefore, a refractive index difference is provided in the two directions transverse to the length of the resonant cavity and a low astigmatism. Furthermore, because the light confinement is strengthened, the light emission efficiency is also enhanced.

Abstract: A method for producing a semiconductor laser including successively growing at least two semiconductor layers simultaneously on a substrate, the finally grown layer not containing aluminum and the layer grown immediately before the finally grown layer containing aluminum, etching a stripe groove through the finally grown layer to expose part of the semiconductor layer containing aluminum, growing a second semiconductor layer not including aluminum on the finally grown layer and the exposed surface of the semiconductor layer containing aluminum, and growing a semiconductor layer including aluminum on the second semiconductor layer not containing aluminum.

Abstract: A semiconductor laser device comprises a substrate (7) formed of p type GaAs, a laser diode portion (10) capable of laser oscillation and a monitor photodiode portion (11) capable of photoelectric conversion formed on substrate (7). The laser diode portion (10) and the monitor photodiode portion (11) are both formed of an epitaxial separating layer (6) of p type AlAs, an epitaxial layer group (23) mainly formed of a material of AlGaAs system and an epitaxial window layer (9) formed on a cleavage plane of this epitaxial layer group (23). The cleavage plane of the epitaxial window layer (9) on the side of the laser diode portion (10) constitutes a laser resonator plane (16) for laser light output of said laser diode portion (10) while the cleavage plane of the epitaxial window layer (9) on the monitor photodiode portion (11) constitutes a light receiving plane (17) for receiving the laser light outputted from the laser resonator plane (16).

Abstract: A semiconductor laser device comprises a substrate (7) formed of p type GaAs, a laser diode portion (10) capable of laser oscillation and a monitor photodiode portion (11) capable of photoelectric conversion formed on substrate (7). The laser diode portion (10) and the monitor photodiode portion (11) are both formed of an epitaxial separating layer (6) of p type AlAs, an epitaxial layer group (23) mainly formed of a material of AlGaAs system and an epitaxial window layer (9) formed on a cleavage plane of this epitaxial layer group (23). The cleavage plane of the epitaxial window layer (9) on the side of the laser diode portion (10) constitutes a laser resonator plane (16) for laser light output of said laser diode portion (10) while the cleavage plane of the epitaxial window layer (9) on the monitor photodiode portion (11) constitutes a light receiving plane (17) for receiving the laser light outputted from the laser resonator plane (16).

Abstract: A radiation-resistant grease that is stable under elevated temperatures is disclosed. The grease is prepared by mixing a bentonite-based thickening agent with a base oil composed of m-(m-phenoxyphenoxy)diphenyl, pentaphenyl ether, a monoalkyltriphenyl ether or a monoalkyltetraphenyl ether (provided that the alkyl group contains 6-20 carbon atoms). To the mixture is added, if necessary, a gelling aid composed of an aliphatic alcohol, an aliphatic ketone and/or an aliphatic carbonate ester.

Abstract: A fluoroalkoxy cyclic phosphonitrile ester represented by the formula (1)[H(CF.sub.2 CF.sub.2)mCH.sub.2 O].sub.2 n-l[CF.sub.3 CF.sub.2 CH.sub.2 O]lPnNn (1)wherein (CF.sub.2 CF.sub.2)m is a single segment of the unit (CF.sub.2 CF.sub.2) multiplied by an integer or indicates conjoint presence of segments having different chain lengths and each comprising the unit (CF.sub.2 CF.sub.2) multiplied by an integer, m is 2 in the case of the single segment or, in the case of the presence of segments of different chain lengths, represents the average of the chain lengths, means the average number of repeating units (CF.sub.2 CF.sub.2) and is in the range of 1.3.ltoreq.m.ltoreq.2.8, l is in the range of 2n-1.gtoreq.l.gtoreq.1, and n is the number of repeating PN units of the phosphonitrile cyclic skeleton, or represents the average number of repeating PN units and is a real number in the range of 3.ltoreq.n.ltoreq.4.3 when rings of different numbers of repeating units are conjointly present.

Abstract: A radiation-resistant grease employed in various machines at nuclear facilities, based on (A) an oil principally composed of a phenoxyphenoxydiphenyl and a mono- and/or dialkyldiphenyl ether and (B) a bentonite based thickening agent, if necessary, together with (C) a gelling aid of alcohol, ketone, or carbonate ester.

Abstract: An oil blend having resistance to ionizing radiation comprising the following components is herein disclosed:A. 25 to 75 wt % of 0-70 wt % of o-(m-phenoxyphenoxy)diphenyl and 100-30 wt % of m-(m-phenoxyphenoxy)diphenyl; andB. 75 to 25 wt % of a monoalkyldiphenyl ether or dialkyldiphenyl ether.This oil blend has a pour point of 0.degree. C. or below and has a G-value of 0.1 or lower for the evolution of decomposition gases under irradiation with ionizing radiation. Said ethers have 10 to 20 carbon atoms in the alkyl moiety.