Abstract: A bellows-form boot for universal joint which is formed integrally of a le-diameter cylindrical portion and a small-diameter cylindrical portion at both ends, the former being adapted to be fitted to a joint case housing therein the universal joint and the latter to a driving shaft, a central annular bellows portion having ridge portions whose diameters are tapered down toward the small-diameter portion, and a bracing boss portion extending between the large-diameter portion and the bellows portion. The boss portion has a wall thickness of 2 to 3 times the average wall thickness of the bellows portion and is profiled so that the inner face thereof may abuttingly contact with the edge face of the joint case and the outer face thereof is flush with the outer face of the bellows portion in the mutual joining area.

Abstract: In a laser of such type that the distribution of the effective refractive index varies in a direction which is along the face of its active layer and perpendicular to the direction of the laser light transmission, thereby defining the active region to be between a pair of refractive index changing zones, the refractive indexes of a pair of end surfaces of a laser resonator (i.e. the active region) is made smaller than the intrinsic refractive indexes of the cleavage face of the active layer.

Abstract: A mounting of semiconductor laser chip on a heat sink or metal mount is improved so as to enable high accuracy of position and direction. A heat sink or metal mount, on which a semiconductor laser chip is mounted, comprises two parts, namely a main mount or larger portion and a sub-mount or smaller portion. The semiconductor laser chip is soldered by a solder layer on the sub-mount utilizing a microscope so as to assure an accurate position and an accurate direction with respect to the sub-mount. Then, the sub-mount is soldered on the main mount by a solder layer with an accurate relation both in position and direction by engaging a linear ridge as a first engaging means provided on the upper face of the main mount with a straight groove and a rear end face as a second engaging means. As a result of the above-mentioned structure, accurate position and direction of the semiconductor laser chip with respect to the mount is easily obtainable with a high yield.

Abstract: A mounting of semiconductor laser chip on a heat sink or metal mount is improved so as to enable high accuracy of position and direction. A heat sink or metal mount, on which a semiconductor laser chip is mounted, comprises two parts, namely a main mount or larger portion and a sub-mount or smaller portion. The semiconductor laser chip is soldered by a solder layer on the sub-mount utilizing a microscope so as to assure an accurate position and an accurate direction with respect to the sub-mount. Then, the sub-mount is soldered on the main mount by a solder layer with an accurate relation both in position and direction by engaging a linear ridge as a first engaging means provided on the upper face of the main mount with a straight groove and a rear end face as a second engaging means, or by engaging a square recess as a first engaging means and the square bottom of the sub-mount as a second engaging means with each other.

Abstract: On a semiconductor laser substrate, a groove of tapered width is formed, and at least one crystal layer is formed on the substrate. The crystal layer is usable as a waveguide with two light input ends l.sub.1 and l.sub.2 and one light output end l.sub.3 as shown in FIG. 4(C).

Abstract: In a semiconductor laser of terraced substrate type, comprising on a terraced substrate (11) of n-GaAs substrate, a first clad layer (12) of n-GaAlAs, an active layer (13) of non-doped GaAlAs, a second clad layer (14) of p-GaAlAs and a current limiting layer (15) of n-GaAs, and further thereon a thick overriding layer (19) of n-GaAlAs with strip shaped opening (191), are epitaxially formed, and a current injection layer (16) is formed by Zn diffusion through the opening (191) in a manner one corner (161) of the injection front penetrate the current limiting layer (15) and reaches the second clad layer (14). By means of thick overriding layer (19), shortcircuiting between the active layer (13) and a p-side electrode (7) is prevented.

Abstract: A stem for a semiconductor laser device of a terraced substrate structure which has a tilted active layer against flat parts of the substrate, the stem comprises a base plate and a heat sink block, a flat face of the heat sink block for bonding the semiconductor laser device thereonto is tilted with respect to a base face of the base plate; this stem has features that the polarization direction of the lased light from the semiconductor laser device can be set to be parallel to (or perpendicular to) the base face of the base plate, and therefore it becomes much easier to make adjustments related with the polarization direction of the lased light.

Abstract: A terrace-substrate laser is improved by forming a stripe-shaped impurity diffused current-injection region (27) from the cap layer (25) at least so as to reach the oblique lasing region (231) of the active layer (23), so that the corner part of the current injection region (27) touches the lasing region (231); thereby current injection efficiency to the lasing region is highly improved and the injected current is effectively limited in the oblique lasing region even when a large current is injected, and furthermore, a threshold current can be greatly reduced. This laser can perform a stable fundamental transverse mode oscillation even at a large current operation.

Abstract: In a terraced substrate type semiconductor laser comprising a semiconductor substrate (11) having a step (T) on its principal face, an active layer (13) with an oblique central region (131), defined between two bendings, as stripe-shaped lasing region near the foot of the step part (T) of the substrate (11), and a clad layer (14) formed on the active layer (13),The device is characterized by comprising a current injection region (22) which is formed by diffusing an impurity, in a manner that a diffusion front corner (221) penetrate the clad layer (14) and contacts the oblique lasing region (131) thereby to form the current injection path (221) very narrow and closely to the central part of the stripe-shaped lasing region (13), thereby effectively confining the injected current to the lasing region (131) and hence attaining very low threshold current and very high external differential quantum efficiency.

Abstract: In a laser comprising a GaAs substrate, an active layer of GaAlAs put between a first and a second clad layers, a buffer layer is disposed between said first clad layer and said substrate, and thermal expansion coefficient of the buffer layer is selected smaller than that of said active layer; thereby an internal stress of the active layer is released and lifetime of the laser is very much prolonged.

Abstract: On an n-type semiconductor substrate having a ridge part of stripe-shaped pattern, the following layers are formed by liquid phase sequential epitaxial growth: an undoped active layer; a p-type clad layer; and an n-type isolation layer. Thereafter, a Cd impurity is diffused in the isolation layer in a stripe-shaped pattern at the position above the ridge part, thereby forming a p+-type conduction region in the central part of the isolation layer. By forming the stripe-shaped ridge part on the substrate overriding the active layer, the injected current is effectively confined to the lasing region which is the thinner part of the active layer and is on the ridge part. Therefore the threshold current is decreased. Accordingly, the light lased in the active layer is effectively confined in a stripe-shaped lasing region thereof, and a stable transverse mode of lasing is obtainable.

Abstract: In a semiconductor laser which has epitaxial layers including an active layer on a semiconductor substrate, a buffer layer is formed neighboring the active layer, in order to prevent undesirable diffusion of a highly diffusing dopant (Zn) into the active layer from an adjacent layer such as the second clad layer. The buffer layer has the same conductivity as that of the adjacent layer, has a broader energy gap than the active layer, and the dopant of the buffer layer is less diffusing than that of the adjacent layer.

Abstract: In a semiconductor laser, an n-type first clad layer, an undoped active layer, and a p-type second clad layer are formed on an n-type semiconductor substrate by liquid phase sequential epitaxial growth. The second clad layer is photo-etched to form a stripe-shaped thicker part at the center and thinner parts on both sides thereof. Thereafter, an n-type isolation layer is further epitaxially formed, and a Zn impurity is diffused in a thinner part of the isolation layer in a stripe-shaped pattern at the position above the thicker part, thereby forming a p+-type conduction region in the central part of the thinner part of the n-type isolation layer. By forming the stripe-shaped ridge part in the clad layer, light lased in the active layer is effectively confined in a stripe-shaped part thereof which is underneath the ridge part. Therefore, a stable transverse mode of lasing results.

Abstract: A terraced-substrate structure semiconductor laser in accordance with the present invention comprises:a terrace-shaped semiconductor substrate having an upper face, a lower face and a step part disposed between said upper face and said lower face,a clad layer formed on said terrace shaped semiconductor substrate and including at least an upper part formed on said upper face and a step part having a triangular section and formed at a corner defined by said lower face and said step part, said step part being thicker than said upper part,an active layer formed on said first clad layer and including a horizontal upper part formed on said upper part of said first clad layer and an oblique lasing region formed oblique on said step part of said first clad layer, but excluding a lower horizontal part, hitherto formed on said lower face,a current injection electrode having a stripe shaped injection face disposed above said lasing region,the improvement is that said active layer is terminated substantially at a lower e

Abstract: In a semiconductor laser a semiconductor substrate has a terrace structure in a manner to have an upper face, a lower face, and a step part disposed between the upper and lower faces. A clad layer is formed on the semiconductor substrate having an upper part, a lower part, and a central part. The upper part is on the upper face and the step part. The lower part is on the lower face and the central part connecting the upper and lower parts and is thicker than the upper and lower parts in a manner that a step-shaped downward-bending surface of the central part is located above the lower face. An active layer formed on the clad layer includes an upper lateral part, a lower lateral part, a center part connecting the upper and lower lateral parts, with a lasing region being a part of the upper lateral part which is near a bending part of the step-shaped downward-bending surface.

Abstract: In a semiconductor laser comprising a terrace-shaped semiconductor substrate, a first clad layer formed on the semiconductor substrate, an active layer formed on the first clad layer and having two discontinuity places at bending portions of the first clad layer, a second clad layer formed on the active layer, and a current injection electrode above a lasing region in the active layer, the improvement is that a stable fundamental transverse lasing mode and a circular laser beam are obtainable from the lasing region definitely separated by two discontinuity places in the active layer.

Abstract: A semiconductor laser is comprised of a terrace shaped substrate andepitaxially grown layers including an active layer on the substrate. The active layer has an oblique active region formed between an upper horizontal part on the thicker part of the substrate and a lower horizontal part on the thinner part of the substrate. The laser is characterized by a current limiting layer of high resistivity or a layer forming a current limiting p-n junction with the substrate between the lower horizontal part of the active layer and the thinner part of the substrate, thereby limiting the path of the current from the active layer to the substrate almost horizontally through the vertical step wall part between the thinner part and the thicker part.