Mitsui Petrochemical Industries, Ltd.

Mitsui Chemicals, Inc.

The Furukawa Electric Co., Ltd.

Yasuo Oeda

Mitsugu Terada

Yuichiro Terashi

Ken Ohmata

Kiyofumi Muro

Tsuyoshi Fujimoto

Michito Uehara

Hideaki Shibata

Satoru Okada

Yumi Naito

Kazuo Shimazaki

Kouichi Igarashi

Atsushi Okubo

Takeshi Koiso

Yoshikazu Yamada

Shuntaro Watanabe

Michio Okubo

A semiconductor laser device includes a layer structure of a first conductive cladding layer, an active layer, and a second conductive cladding layer sequentially grown on a first conductive semiconductor substrate; and a light emitting facet from which a laser beam having a first wavelength is emitted. Refractive indexes of the first and the second conductive cladding layers with respect to the first wavelength are lower than an effective refractive index with respect to the first wavelength. With respect to a light having a second wavelength incident on the light emitting facet from outside, the refractive index of at least one of the first and the second conductive cladding layers is equal to or higher than the effective refractive index with respect to the second wavelength.

Semiconductor laser device, semiconductor laser module, and optical fiber amplifier

On a substrate of n-type GaAs are sequentially formed an n-type cladding layer (AlGaAs, Al content x&equals;0.07, thickness t&equals;2.86 &mgr;m), an n-type optical waveguide layer (GaAs, t&equals;0.49 &mgr;m), an n-type carrier blocking layer (AlGaAs, x&equals;0.40, t&equals;0.03 &mgr;m), an active layer (composed of an In Ga As quantum well layer and a GaAs barrier layer), a p-type carrier blocking layer (AlGaAs, x&equals;0.40, t&equals;0.03 &mgr;m), a p-type optical waveguide layer (GaAs, t&equals;0.49 &mgr;m), a p-type cladding layer (AlGaAs, x&equals;0.20, t&equals;1.08 &mgr;m), and a p-type cap layer (GaAs) in which a pair of n-type current blocking layers (GaAs) are buried. With this construction, the occurrence of a wavelength spit due to a higher-order mode can be inhibited thereby stabilizing a higher power operation.

Semiconductor laser apparatus

A semiconductor laser device includes: an active layer; upper waveguide layers and a lower waveguide layer sandwiching the active layer therebetween; upper and lower cladding layers sandwiching the active layer and the upper and lower waveguide layers therebetween; and a current-narrowing layer defining a current-injection region for injecting current to the active layer, wherein a diffraction grating having a periodical structure in a resonance cavity direction is buried in any one of the waveguide layers, the diffraction grating being present in at least a part of the current-injection region; and the waveguide layer in which the diffraction grating is buried and the cladding layer adjoining to that waveguide layer forms an interface which is substantially flat in the resonance cavity direction. With the constitution, a waveguide structure which has a diffraction grating offering a higher flexibility in design and manufacture in terms of the coupling efficiency is realized, thereby easily providing a dynamic single-mode semiconductor laser device with higher reproducibility, yield and reliability.

Semiconductor laser device, semiconductor laser module, rare-earth-element-doped optical fiber amplifier and fiber laser

Optical guide layers are formed on both faces of the active layer, respectively, which optical guide layers have a band gap wider than that of the active layer, an n-type cladding layer and a p-type cladding layer respectively formed so as to sandwich the active layer and the optical guide layers therebetween, which cladding layers have a band gap wider than those of the optical guide layers, and carrier blocking layers are respectively formed between the active layer and the optical guide layers, which carrier blocking layers have a band gap wider than those of the active layer and the optical guide layers. The refractive index of the p-type cladding layer is lower than that of the n-type cladding layer. With such constitution inner losses are limited to a low level, as free carrier absorption is reduced, and the electric and thermal resistances of a semiconductor laser device are reduced, with the result that the laser device is enhanced in efficiency and output power.

Semiconductor laser device

A semiconductor laser light source includes: a semiconductor laser array which emits laser beams whose polarization planes are parallel to each other and whose divergent angles .theta.z and .theta.x in two orthogonal directions satisfy an inequality .theta.z&gt;.theta.x; a cylindrical lens which converges the laser beams emitted from the semiconductor laser array in a direction that decreases the divergent angle .theta.z; a wave plate which controls the direction of polarization so that the polarization planes of the laser beams having passed through the cylindrical lens are at 90 degrees to each other; a birefringent optical element which merges by the birefringent effect the optical paths of the laser beams having passed through the wave plate; and a light emitting surface which converges the laser beams merged by the birefringent optical element in a direction that decreases the divergent angle .theta.x. Thus, the efficiency of merging the laser beams and the efficiency of joining the laser beams to the succeeding optical system can be greatly improved.

Semiconductor laser light source and solid-state laser apparatus

A laser light, whose wavelength is to be measured, is introduced into an etalon, a concentric circular interference stripe derived from the etalon is irradiated onto a one-dimensional photodetector array and a diameter of the interference stripe is measured to measure the wavelength of the laser light. Alternatively, if a reference laser light of known wavelength is introduced into the etalon, as described above, a wavelength measurement of extremely high accuracy can be made without being affected by positional deviations of the optical system.

Method and apparatus for detecting wavelength of laser beam

Discharge exciting excimer laser device

Angles of inclination of the two wavelength selection elements arranged on an optical path of a laser beam source are varied to make a laser output variable. Light transmitting ranges of the two wavelength selection elements are coincided with each other so as to adjust the light wavelength bands, thereby the laser beam is narrowed without increasing its fineness.

Laser device

A gas laser apparatus having transparent laser windows provided on a laser chamber body, in which operating gases is sealed if necessary, comprising circulation means connected to the laser chamber body through an intake port and a discharge port for circulating gases within the laser chamber body and filtration means disposed in said circulation means, further comprising cutoff means for preventing the laser windows from being stained and open and closeably cutting off between the laser chamber body and the laser windows, and having a construction wherein in replacing the laser window, the cutoff means is once placed in a cutoff state, and the laser window is separated from the laser chamber body to place the laser window.

Gas laser apparatus

This invention is provided with a wavelength selecting means for uses in selectively receiving beam in compliance with each of a reference beam and a measured beam in order to simplify a correction or comparison of oscillating wavelengths in the laser device and further to improve a reliability and a controlling responsive speed.

Growing community of inventors

Sodegaura, Japan

Yasuo Oeda