Hitachi, Ltd.

Ryoichi Ito

Satoshi Nakamura

Naoki Chinone

Kunio Aiki

Toshihisa Tsukada

Yoshito Tsunoda

Kimio Tatsuno

Noriyuki Shige

Toshimitsu Miyauchi

Katuaki Chiba

Ichiro Ikushima

Yutaka Takeda

Atsutoshi Doi

Kazutoshi Saito

Yoshimitsu Sasaki

A semiconductor laser device is formed of a semiconductor material assembly including a first semiconductor layer having an active region formed directly by crystal growth on a substrate for the crystal growth having on the surface thereof a second semiconductor layer. A third semiconductor layer is also formed on the first layer. The refractive index of each of the second semiconductor material region and the third semiconductor layer is smaller than that of the first semiconductor layer while the band gap of each of the second semiconductor material region and the third semiconductor layer is broader than that of the first semiconductor layer. In order to provide mode stabilization even at long wavelength, the thickness of the active region formed at the interface between said first semiconductor layer and said substrate for crystal growth is made larger than the thickness of the other portions in the first semiconductor layer so that the effective refractive index to laser beams is changed stepwise in a direction perpendicular to the direction of the laser beams.

Semiconductor laser device

A semiconductor laser device is capable of producing an increased optical output power with improved optical characteristics without being subjected to mode distortions in the output beam, while retaining advantageous features inherent to a semiconductor laser device of a buried heterostructure. The semiconductor laser device comprises an optical confinement region which is constituted by at least first, second, third and fourth semiconductor layers successively laminated on a predetemined semiconductor substrate. The second semiconductor layer has a relatively small refractive index and a relatively wide band gap as compared with those of the third semiconductor layer, while the first and the fourth semiconductor layers which are of the conductivity types opposite to each other have relatively small refractive indexes as compared with the second and the third semiconductor layers. The band gaps of the fourth and the second semiconductor layers are relatively large as compared with that of the third semiconductor layer. Difference in the band gap at least between the second and the third semiconductor layers is not smaller than 0.15 eV.

An optical head comprising a semiconductor laser array which is used as a light source, and an optical system which guides laser beams from the array to a predetermined recording medium. The beam from one lasing point of the array is modulated by predetermined information and is used as a recording beam, while the beam from another lasing point is continuously oscillated and is used as a playback beam.

Optical head for a videodisc player/recorder

A light-emitting semiconductor device is provided having a light-emitting semiconductor element emitting light in two directions. The light-emitting element is disposed in a housing so that one light-emitting face of the semiconductor element adjacent a heat sink, and a light guide is arranged to confront the other light-emitting face of the semiconductor element and to guide light from said other light-emitting face to the outside of the housing. In this device, the end face of the light guide confronting said other light-emitting face of the semiconductor element includes a face substantially inclined to the optical axis of light emitted from the semiconductor element.

Light-emitting semiconductor device

A mount for a light emitting device, which includes a first silicon substrate provided with first holding grooves of trapezoidal cross-section for mounting optical parts arranged in the vicinity of the light emitting plane of a light emitting element and a positioning groove for the light emitting element on the surface thereof, a second silicon substrate provided with second holding grooves having a trapezoidal cross-section similar to that of the first grooves for holding the optical parts and a hole portion for inserting the light emitting element, and a covering member for air tightly covering the hole portion, whereby the optical parts and the light emitting element of the light emitting device are tightly sealed by the above-stated means. The first and second holding grooves have the silicon crystal plane of (111) as both the side surfaces of their trapezoidal cross sections, and extend in the silicon crystal orientation of &lt;110&gt;.

Mount for a light emitting device

A semiconductor laser having a structure such that a narrow strip mesa is formed above a laser active layer in a hetero-structure crystal so that it can generate a laser beam of improved optical property.

Growing community of inventors

Hachioji, Japan

Ryoichi Ito