Mitsubishi Denki Kabushiki Kaisha

Mitsubishi Electric Corporation

Motoharu Miyashita

Shoichi Karakida

Yutaka Mihashi

Norio Hayafuji

Hirotaka Kizuki

Yuji Ohkura

Takehiro Nishida

Yasutomo Kajikawa

Takashi Nishimura

Akihiro Shima

Tsutomu Yamaguchi

Yutaka Nagai

Tatsuya Kimura

Tadashi Kimura

Kyosuke Kuramoto

Yasuaki Yoshida

Harumi Nishiguchi

Chikara Watatani

Nobuyoshi Ogasawara

Diethard Marx

Yuji Iwai

Motoko Sasaki

Ken-ichi Ono

Provided here are: semiconductor layers comprised of an n-type cladding layer formed on a surface of an n-type GaAs substrate, active layers formed on surfaces of the n-type cladding layer, p-type cladding layers formed on surfaces of the active layers, and p-type contact layers formed on surfaces of the p-type cladding layers, the p-type cladding layers and the p-type contact layers being formed to have a ridges; insulating films covering surfaces of the semiconductor layers but having openings on surfaces of the p-type contact layer; and conductive layers connected to the p-type contact layers through the openings, the conductive layers being formed on surfaces of the insulating films to cover planar portions provided in the semiconductor layers adjacently to the ridges; wherein, together with the conductive layers, convex sidewalls are provided to be placed over portions of the planar portions at their sides nearer to the ridges.

Semiconductor laser element, method for manufacturing same, and semiconductor laser device

A semiconductor laser device is configured so that, on at least one of the respective opposing surfaces of a semiconductor laser chip and a sub-mount and the respective opposing surfaces of the sub-mount and a heatsink, one or more treatment regions are provided where adhesion of a bonding material or bonding material used for their bonding is reduced, wherein the one or more treatment regions are placed to define, in a traveling direction of light, different coverages depending on a position in an array direction of multiple light emitting regions.

Semiconductor laser device

A monolithic semiconductor laser having plural semiconductor lasers having different emission wavelengths from each other, including: a semiconductor substrate; a first double hetero-structure formed within a first area on the semiconductor substrate and having first clad layers disposed above and below a first active layer; and a second double hetero-structure formed within a second area on the semiconductor substrate and having second clad layers disposed above and below a second active layer. The first and second active layers are made of different semiconductor materials from each other. The first clad layers above and below the first active layer are of approximately the same semiconductor materials and the second clad layers above and below the second active layer are of approximately the same semiconductor materials.

Monolithic semiconductor laser and method of manufacturing the same

A semiconductor laser apparatus includes multiple light emitting points, and a simple ridge stripe structure for each of the light emitting points. At least one of the light emitting points is disposed at a location that is 0% to 15% of the width of a substrate of the apparatus from the center, in the width direction, of the substrate.

Semiconductor laser apparatus

A semiconductor laser device exhibiting a reduced threshold current with less deterioration in temperature properties in current-optical output performance and excellent beam properties. The semiconductor laser device has a current blocking layer of n-AlInP having a stripe-shaped opening disposed on a first upper cladding layer, the first upper cladding layer and the current blocking layer facing the opening respectively are covered by a buffer layer of p-Al Ga As and a second upper cladding layer of p-(Al Ga ) In P is disposed on the buffer layer, to prevent lattice defect formation during growth of a crystalline layer on the surface of the current blocking layer facing the opening.

A forward mesa ridge-embedded semiconductor laser device provides a high power output and includes a base portion of a forward mesa ridge having a narrow width to stabilize transverse mode oscillation and an upper cladding layer having a thickness sufficient to reduce loss of the laser beam, a top portion of the forward mesa ridge being interposed between parts of the current blocking layer to reduce the device resistance. The upper cladding layer includes a first cladding layer having the forward mesa ridge and a second cladding layer opposite the first cladding layer. The second cladding layer is deposited over the first cladding layer through the forward mesa ridge and a current blocking layer is positioned on both sides of the forward mesa ridge.

Semiconductor laser device and process for manufacturing the same

A semiconductor laser device on a GaAs substrate and having an oscillation wavelength of 1.3 &mgr;m or 1.55 &mgr;m and a method of producing the laser device. The laser device has a BTlGaAs active layer that lattice matches with the GaAs substrate. To grow the BTlGaAs active layer, organometallic vapor phase deposition is employed with cyclopentadienyl thallium as the source of Tl.

Semiconductor laser device and method of producing the same

A stress compensation type semiconductor laser emitting laser light of 0.98 .mu.m.about.1.02 .mu.m wavelength includes a semiconductor substrate, a cladding layer disposed on the semiconductor substrate, and a multiple quantum well structure active layer disposed on the cladding layer and comprising a plurality of well layers and barrier layers. In the laser, when the number, strain, and thickness of the well layers are n, f.sub.w, and t.sub.w, respectively, and the number, strain, and thickness of the barrier layers are m, f.sub.b, and t.sub.b, respectively, the average strain f.sub.av of the well layers and the barrier layers, and the total thickness t.sub.total of the well layers and the barrier layers is given by ##EQU1## where .upsilon. is the Poisson ratio, b.sub.o is the magnitude of a Burgers vector of a perfect dislocation, b.sub.p is the magnitude of a Burgers vector of partial dislocation, and r.sub.c is the half loop radius of a dislocation. Therefore, an active layer having required stress compensation performance is realized with high reliability and high reproducibility.

Stress compensation type semiconductor laser

A semiconductor laser includes a first conductivity type GaAs substrate; a AlGaAs double heterojunction structure disposed on the GaAs substrate and including an upper cladding layer having a mesa ridge stripe with a side surface that makes an angle larger than 90.degree. with a front surface of the upper cladding layer; a first current blocking layer of first conductivity type AlGaAs; and a second current blocking layer of first conductivity type AlGaAs, the first and second current blocking layers covering the mesa ridge stripe. The Al compositions of the first and second current blocking layers are larger than that of the upper cladding layer, maintaining an equivalent refractive index of an active region higher than that of other portions of the semiconductor laser. As a result, the differences between the lattice constant of the second current blocking layer and the GaAs substrate or the AlGaAs upper cladding layer are smaller than in prior art semiconductor lasers. Since the second current blocking layer is in the vicinity of the active region in the mesa ridge stripe, stress applied to the active region is reduced, thereby producing a semiconductor laser that facilitates ridge width control and burying layer growth, and with improved reliability.

Semiconductor laser

A method of fabricating a semiconductor device includes: forming multiatomic steps by MOCVD on a (110) semiconductor substrate inclined at an angle toward the �001! direction or the �111! direction; and growing at least one double heterostructure including a first compound semiconductor and a second compound semiconductor having a smaller band gap than the first compound semiconductor to form quantum wires of the second compound semiconductor at edges of the multiatomic steps. Multiatomic steps having step edges along the longitudinal direction of the wire have improved linearity, and thus, quantum wires can be fabricated with improved controllability.

Semiconductor device including quantum wells or quantum wires and method

A pulsation laser includes an n-type AlGaAs cladding layer on an n-type GaAs substrate, three quantum well active layers having central increased thickness regions and disposed on the cladding layer, and a p-type AlGaAs cladding layer disposed on the quantum well active layer. The increased thickness region of the active layer is not more than one-quarter of the length of the resonator of the laser.

Pulsation laser having an active region with a thicker central region in

A method of fabricating a semiconductor laser device includes successively forming an active layer and upper cladding layers on a lower cladding layer, etching and removing portions except regions of the upper cladding layers where a current is to flow to form a stripe-shaped ridge structure, and forming a buffer layer comprising Al.sub.x Ga.sub.1-x As having an Al composition ratio x of 0 to 0.3 on a surface of the upper cladding layers exposed by the etching and forming a current blocking layer of first conductivity type Al.sub.y Ga.sub.1-y As having an Al composition ratio y of at least 0.5 on the buffer layer to bury portions of the upper cladding layers which are not removed by the etching process. Therefore, since the layer grown on the upper cladding layer exposed by etching of AlGaAs or GaAs having a low Al composition ratio (0-0.3), three-dimensional growth of and crystalline defects in the buffer layer are suppressed. Current leakage is suppressed, so that a semiconductor laser device having a low threshold current and a high efficiency is fabricated with a stable yield.

Semiconductor laser device and method of fabricating semiconductor laser

A semiconductor laser includes a ridge structure includes a cladding layer having a thermal expansion coefficient. Current blocking structures are disposed at both sides of the ridge structure and include Al.sub.x Ga.sub.1-x As first current blocking layers having an Al composition x larger than 0.7 and contacting the ridge structure. In this structure, even when the Al composition of the first current blocking layers is reduced at both sides of the ridge structure, the wavelength of light absorbed by the first current blocking layers does not exceed the wavelength of laser light produced in the active layer. Therefore, unwanted absorption of the laser light at both sides of the ridge structure is avoided, resulting in a semiconductor laser with improved laser characteristics.

A semiconductor laser device includes a semiconductor substrate of a first conductivity type; opposed light emitting facets; a double heterojunction structure disposed on the semiconductor substrate and including an optical waveguide that extends between the facets and comprises a light emitting region and a lens region, the lens region being between the light emitting region and one of the facets, the double heterojunction structure including a plurality of AlGaAs series compound semiconductor layers which are thicker in the light emitting region than in the lens region; and a current blocking structure disposed on both sides of the double heterojunction structure and including a lower AlGaAs series compound semiconductor layer of the first conductivity type, an intermediate AlGaAs series compound semiconductor layer of a second conductivity type, opposite the first conductivity type, and an upper AlGaAs series compound semiconductor layer of the first conductivity type. Therefore, a reactive current that does not contribute to laser oscillation is prevented from flowing through the current blocking structure.

A semiconductor laser device includes, on a first conductivity type GaAs substrate, successively, a first conductivity type GaAs buffer layer, a first conductivity type Al.sub.s Ga.sub.1-s As (0&lt;s&lt;1) cladding layer, a quantum well active layer having a structure that can produce an oscillation wavelength of 0.9.about.1.2 .mu.m and including a well layer comprising In.sub.x Ga.sub.1-x As (0&lt;x&lt;1) and a barrier layer comprising Al.sub.y Ga.sub.1-y As (0&lt;y&lt;s), a second conductivity type Al.sub.t Ga.sub.1-t As (1&lt;t&lt;y) upper cladding layer, a second conductivity type GaAs contact layer, and a multiple reflection film layer alternatingly laminating first and second semiconductor materials which have the same conductivity type as the adjacent semiconductor materials and have the different refractive indices in number of layers, first and second electrodes, and a pair of laser resonator facets perpendicular to the active layer and the multiple reflection film layer. Therefore, a semiconductor laser device in which generation of large mode hops is suppressed, the generation of kinks is reduced, and stable and high power output laser beams are produced is realized.

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Tokyo, Japan

Motoharu Miyashita