Hitachi, Ltd.

Takashi Kajimura

Naoki Chinone

Kazuhisa Uomi

Yuichi Ono

Jun-ichi Umeda

Takao Kuroda

Michiharu Nakamura

Toshihiro Kawano

Tadashi Fukuzawa

Shinichi Nakatsuka

Tsukuru Ohtoshi

Yasutoshi Kashiwada

Masahiko Kondow

Shigekazu Minagawa

Toshiaki Tanaka

Kunio Aiki

Shigeo Yamashita

Shin'ichi Nakatsuka

Misuzu Yoshizawa

Shin Satoh

Katsutoshi Saito

Hisao Nakashima

Hideaki Matsueda

Hiroshi Matsuda

Toshikazu Shimada

Masayoshi Kobayashi

Kenji Uchida

Yoshifumi Katayama

Motohisa Hirao

Noriyuki Shige

Hirobumi Ouchi

Akio Ohishi

Yuuichi Ono

Kazutoshi Saito

Yoshimitsu Sasaki

Akemi Yamanaka

Shinichi Nakatuka

Misuzu Sagawa

A hetero crystalline structure consisting of semiconductor materials of a zincblende-structure and wurtzite-structure. For example, formed on a semiconductor substrate having a crystal face of (100) of the zincblende structure is a semiconductor material of the wurtzite-structure in its bulk state as a film of the same zincblende-structure as the semiconductor substrate.

Hetero crystalline structure and semiconductor device using it

An optielectronic device comprising a substrate crystal whose crystal plane is a (n11) plane tilted from the (100) plane toward the [110] direction, or [110] direction where (n&gt;1). When the substrate is applied to an AlGaInP semiconductor laser, the optical device can be cleaved into a rectangular shape, as in the case of a (100) substrate crystal, resulting in easy handling of the chips and also is effective for making the lasting wavelength shorter, lowering the threshold current density for lasing, improving the continuous lasing temperature, etc. Furthermore, semiconductor lasers of different lasing wavelengths can be prepared under good control. Furthermore, a doping efficiency having no dependence on a tilt angle can be obtained by proper selection of a dopant. For example, Si is suitable as an n-type dopant entering sites of group III atom on an (n11) A plane (n.gtoreq.2).

Optoelectronic devices

A semiconductor laser having a stripe-like lasing region, wherein the structure of the lasing region such as the mechanism of optical guiding of the lateral mode control structure is made different between the central portion in the lasing region and portions close to facets, in order to reduce optical feedback induced noise and astigmatism, and to facilitate the manufacture thereof.

Semiconductor laser

A semiconductor laser device including a plurality of oscillation stripes so that phase locked oscillation can be generated at adjacent oscillation stripes is disclosed, in which device dummy regions for transmitting a current uncontributive to laser oscillation are arranged on both sides of an oscillation stripe region containing the oscillation stripes.

Semiconductor laser device

A high-power low-noise semiconductor laser device required for light sources for an erasable optical disc is a self-sustained pulsating semiconductor laser device in which an MQW structure is used for an active layer, and thus a kink output power and a light output power by which the self-pulsation is enabled are increased to 10 mW or more and noise is reduced. Another semiconductor laser device of a self-pulsation type has impurities that are doped in the active layer to reduce the self-pulsating frequency to obtain a low-noise characteristic even if higher optical feedback occurs. 259

In a well-known semiconductor laser, a multiple quantum well type active layer consisting of barrier layers and active layers or well layers, each of which has a thickness less than the de Broglie wavelength of electrons, is doped with an impurity, and the impurity density is made higher in the barrier layer than in the well layer. Further, in a case where the multiple quantum well active layer is held between p-type and n-type cladding layers, the well layer is undoped, the part of the barrier layer lying in contact with the well layer is undoped, and the other part of the barrier layer close to the p-type cladding layer is put into the n-conductivity type while that of the barrier layer close to the n-type cladding layer is put into the n-conductivity type. Desirably, the impurity density should range from about 1.times.10.sup.18 to about 1.times.10.sup.19 cm.sup.- 3.

Semiconductor laser having a multiple quantum well structure doped with

In a well-known semiconductor laser, a multiple quantum well type active layer consisting of barrier layers and active layers or well layers, each of which has a thickness less than the de Broglie wavelength of electrons, is doped with an impurity, and the impurity density is made higher in the barrier layer than in the well layer. Further, in a case where the multiple quantum well active layer is held between p-type and n-type cladding layers, the well layer is undoped, the part of the barrier layer lying in contact with the well layer is undoped, and the other part of the barrier layer close to the p-type cladding layer is put into the n-conductivity type while that of the barrier layer close to the n-type cladding layer is put into the p-conductivity type.

Semiconductor laser having quantum well active region doped with

In a semiconductor laser device having an active layer and clad layers, lens-like portions which magnify radiation are formed in the active layer and/or a clad layer where the radiation leaks, thereby making it possible to enlarge a stripe width and to produce a fundamental mode oscillation of high output. Futher, a lens-like portion which condenses the radiation is formed at an end face of an emission port for a laser beam, thereby making it possible to narrow a radiant angle of the laser beam.

Semiconductor laser device having a lens-like refractive index

A semiconductor laser having a double hetero structure comprises a cladding layer of In.sub.1-x-y Ga.sub.x Al.sub.y P.sub.1-z As.sub.z (0.ltoreq.x.ltoreq.1, 0.ltoreq.y.ltoreq.1, 0.ltoreq.z.ltoreq.0.5, 0.5.ltoreq.x+y.ltoreq.1) and an active layer of a strained-layer-superlattice of In.sub.1-x-y Ga.sub.x Al.sub.y P.sub.1-z As.sub.z (0.ltoreq.x.ltoreq.1, 0.ltoreq.y.ltoreq.1, 0.ltoreq.z.ltoreq.1, 0.ltoreq.x+y.ltoreq.1) system, thus enabling the lasing of wavelength ranges from infra-red to green.

A semiconductor laser device including at least one of a laser active layer formed of a super lattice and an optical guide layer formed of another super lattice is disclosed in which part of at least one of the super lattices is converted into a mixed crystal by the impurity induced disordering based upon one of impurity diffusion and impurity ion implantation, to divide the super lattice into a first region formed of the mixed crystal and a second region having the super lattice structure, the width of the second region in directions perpendicular to the lengthwise direction of a laser cavity varies along the above lengthwise direction, and the width of a laser excitation region is smaller than the mean value of the width of the second region, to generate laser oscillation having a single transverse mode and a multi longitudinal mode. Thus, the semiconductor laser device emits a laser beam which is small in astigmatism and low in optical feedback noise.

Semiconductor laser device and method of fabricating the same

A stripe groove is formed on a semiconductor substrate and buried by lamination of multiple semiconductor layers, and a channel being lower than the substrate surface is formed outside the groove near at least one mirror edge, such that a laser diode with decreased astigmatism can be produced.

Laser diode

A phased array semiconductor laser has two or more luminous stripes. The number, width or center to center spacing of stripes is made different between the center region and neighborhood of facets of the laser so that the laser may oscillate stably in the fundamental supermode with an optical output of 100 mW or more.

Disclosed is a semiconductor laser wherein an interface layer is provided on an upper cladding layer formed on an active layer, the interface layer having a smaller Al mole ratio than that of the upper cladding layer, thereby preventing oxidation of the semiconductor surface which is exposed to the atmosphere, and thus improving the crystallizability of a semiconductor layer which is to be formed subsequently. By setting the refractive index of this semiconductor layer so as to be smaller than that of the upper cladding layer, light can be confined in the active layer at increased efficiency.

Semiconductor laser device having high optical intensity and reliability

The present invention relates to phased-array semiconductor lasers having a radiation angle turnable by oscillating independently and stably between the fundamental supermode and the higher order supermode and switching the radiation angles by utilizing the property that their radiation angles are different. Optical switching and optical scanning, that have been difficult in the prior art, can be made more easily by use of a semiconductor laser having a turnable radiation angle. The objection of the present invention can be accomplished by disposing separate electrodes at the emission stripes and at the gap between the stripes in the phased-array semiconductor laser. Further, the present invention may be accomplished by dividing at least one stripe electrode in order to form electrode regions. When the current is applied to all the electrodes, oscillation occurs in the highest order mode and the beam is emitted in another direction. When the current is applied to only the electrode exclusive of the electrode regions, oscillation occurs in the fundamental mode and the beam is emitted in a direction vertical to a facet. Moreover, the present invention may be accomplished by disposing electrodes outside the stripe regions of the phased-array semiconductor laser so that oscillation occurs in the fundamental supermode when the electric field is applied to the electrodes and in the higher order mode when the electric field is not applied.

An opto-electronic device has an atomic layer superlattice semiconductor comprising different semiconductor materials periodically piled up, each material having an atomic layer thickness. The superlattice semiconductor has a bandgap different from an alloy semiconductor having equivalently the same composition as the former. In a semiconductor laser, as clad layers, the atomic layer superlattice semiconductor having equivalently the same composition as a Zn.sub.0.42 Cd.sub.0.58 S alloy semiconductor and a larger bandgap than the later is used, and a ZnSe.sub.0.94 S.sub.0.06 alloy semiconductor as an active layer is located between the cladding layers. The double-hetero structure semiconductor laser thus provided can perform the lasing at 470 nm at room temperature.

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Tokyo, Japan

Takashi Kajimura