Abstract: A superluminiscent diode includes: a semiconductor substrate of a first conductivity type lower cladding layer of the first conductivity type is provided on the semiconductor substrate. An active layer is provided on the lower cladding layer. An upper cladding layer of a second conductivity type opposite to the first conductivity type bis provided on the active layer. A current blocking layer of the first conductivity type, buried in the upper cladding layer. The current blocking layer has a stripe-shaped groove serving as a current-injection region. The current-injection region is formed in a manner that is extends from an end face of a chip to the inside of the chip, and has a length shorter than that of the chip. The current blocking layer is made of a material having a band gap energy not greater than that of the active layer and a refractive index not smaller than that of the active layer so that light advancing in the active layer is absorbable.

Abstract: A semiconductor laser including a first conductive type of lower clad layer, active layer, a second conductive type of upper first clad layer, the first conductive type of current blocking layer having a stripe shaped open portion, and the second conductive type of upper second clad layer laminated in order on the first conductive type of GaAs substrate, wherein each portion in contact with the lower clad layer, the active layer, the upper first and second clad layer and at least the upper second clad layer of the current blocking layer is composed of a compound semiconductor to be represented by a formula, in which (Al.sub.x Ga.sub.1-x).sub.y In.sub.1-y P (x is 0<x.ltoreq.1 in the lower and upper first, second clad layers, 0.ltoreq.x<1 in the active layer, a given value y is approximately 0.5 for each layer) within of each range of 0<x.ltoreq.0.75 in the portion in contact with the upper second clad layer of the current blocking layer.

Abstract: An optical communication unit includes a light emitting element for emitting a transmission signal light; a condenser lens for coupling the transmission signal light from the light emitting element to an optical transmission path; and a light receiving element for receiving a receiving signal light from the optical transmission path. A light emitting surface in the light emitting element is formed by a plane tilted to a perpendicular plane in a substrate surface of a chip in the light emitting element.

Abstract: A superluminescent diode includes a semiconductor substrate of a first conductivity type. A lower cladding layer of the first conductivity type is provided on the semiconductor substrate. An active layer is provided on the lower cladding layer. An upper cladding layer of a second conductivity type opposite to the first conductivity type is provided on the active layer. A current blocking layer of the first conductivity type is buried in the upper cladding layer. The current blocking layer has a stripe-shaped groove serving as a current-injection region. The current-injection region is formed in a manner that it extends from an end face of a chip to the inside of the chip, and has a length shorter than that of the chip. The current blocking layer is made of a material having a band gap energy not greater than that of the active layer and a refractive index not smaller than that of the active layer so that light advancing in the active layer is absorbable.

Abstract: A semiconductor laser adaptable for a 3-beam method, including a semiconductor laser chip bonded on a primary plane of a flat submount, the semiconductor laser chip having a thickness of 30 to 80 .mu.m is provided. Also provided is a method for manufacturing a semiconductor laser including the steps of: sequentially stacking layers of compound semiconductor materials on a semiconductor substrate to form a semiconductor laser wafer; mechanically abrading the semiconductor substrate to make it thin; subjecting the mechanically abraded face of the semiconductor substrate to a chemical treatment; forming an electrode film on both sides of the semiconductor laser wafer thus treated; and cutting the semiconductor laser wafer into chips and bonding each of the chips on a submount.

Abstract: A semiconductor laser device comprises: an active layer; a lower clad layer provided below the active layer; an upper clad layer provided above the active layer; and a current blocking layer, provided above the upper clad layer, for limiting an active region of the active layer in a direction along a width to make the active region of a striped form which has a wide portion and a narrow portion. According to the device, coherence of an oscillated laser beam is reduced, thereby to decrease a feedback induced noise when used for a pickup of an optical information recording/reproducing apparatus.

Abstract: The invention is directed to a semiconductor laser wherein the first embodiment is characterized in that the first upper portion cladding layer is assumed to be a double layer construction, the upper layer portion is assumed to be higher in carrier concentration than the lower layer portion, the series resistance component is restrained, so that the sequential direction voltage V.sub.F may be lowered without damaging the other characteristics such as oscillation start current I th and so on.

Abstract: The invention is directed to a semiconductor laser wherein the first embodiment is characterized in that the first upper portion cladding layer is assumed to be a double layer construction, the upper layer portion is assumed to be higher in carrier concentration than the lower layer portion, the series resistance component is restrained, so that the sequential direction voltage V.sub.F may be lowered without damaging the other characteristics such as oscillation start current I th and so on.

Abstract: A molecular beam epitaxy apparatus comprises a growth chamber provided therein with a holder support frame and connected via a first gate valve to a preparation chamber which in turn is connected to a loading chamber via a second gate valve. A first transfer tray arranged in the loading chamber receives a set of substrates from outside and advances into the preparation chamber. A second transfer tray supports a substrate holder in the preparation chamber to allow the set of substrates to be transferred from the first tray onto the holder by the aid of a substrate transfer assembly. The second tray is advanced into the growth chamber to transfer the loaded holder onto the holder support frame.