Kabushiki Kaisha Toshiba

Koichi Gen-ei

Makoto Okada

Akira Tanaka

Seiji Iida

Hideo Shiozawa

Kazuo Fukuoka

A semiconductor laser chip has an emission facet for emitting a laser beam. A sub-mount has a first surface and at least one second surface vertical to the first surface. The semiconductor laser chip is provided on the first surface of the sub-mount. The second surface arranged in line with the emission facet of the semiconductor laser chip is inclined at an angle of 3 to 30 degrees. The inclined second surface reflects reflection light of a sub-beam diffracted from a main beam emitted by the semiconductor laser chip.

Semiconductor laser device which removes influences from returning light of three beams and a method of manufacturing the same

A monolithic two-wavelength semiconductor laser device includes a front end face film on a resonator front end face , and a high-reflectivity end face film as a multilayered film on a resonator rear end face . The front end face film is formed using a low-refractive-index material, and the film thickness is so set that the reflectivity is 20%. The high-reflectivity end face film is formed by alternately stacking thin films of low- and high-refractive-index materials, and the film thickness is so set that the reflectivity is 80%. The film thickness of each of these two end face films is calculated by an optical length d&equals;(&frac14;&plus;j)&times;&lgr;m by using a mean value &lgr;m&equals;(&lgr;1&plus;&lgr;2)/2 of the oscillation wavelengths of the two semiconductor laser diodes. This makes it possible to obtain an end face film having a desired reflectivity and capable of being formed at once, and to fabricate a two-wavelength semiconductor laser device having high reliability, meeting the required performance, and also having high productivity.

Semiconductor laser device and method of fabricating the same

This is a double wavelength semiconductor laser unit having a first laser emitting a light of a first wavelength and a second laser emitting a light of a second wavelength different from the first wavelength. The first and second lasers are merged on a substrate. The first laser has a bulk active layer whose film thickness is 0.01 &mgr;m or more and 0.1 &mgr;m or less. And the second laser has an MQW active layer constituted by stacked structure composed of a quantum well layer and a barrier layer. By employing the bulk active layer for the first laser, it is possible to reduce the band gap discontinuity induced at a boundary between a cladding layer and the bulk active layer, and then decreases an operational voltage, and further improve the reliability of the first laser.

Monolithic multi-wavelength semiconductor laser unit

A semiconductor laser amplifier according to this invention has an optical waveguide layer containing a p-type semiconductor layer in an n-type semiconductor substrate. On one end of the n-type semiconductor substrate, for example, a reflective film is formed as light-reflecting means. In this invention, two optical waveguide layers are arranged so as to form a V with these two layers meeting each other at one end, on which the reflective film is formed, of the substrate.

Growing community of inventors

Ichikawa, Japan

Koichi Gen-ei