Mitsubishi Electric Corporation

Mitsubishi Denki Kabushiki Kaisha

Yuichiro Okunuki

Go Sakaino

Naoki Nakamura

Ayumi Fuchida

Keisuke Matsumoto

Tohru Takiguchi

Masayoshi Takemi

Yosuke Suzuki

Chikara Watatani

Ryoko Suzuki

Tetsuya Uetsuji

Ryosuke Nagao

An optical device includes: lasers output first light from a front-end side and output second light from a rear-end side; an optical multiplexer circuit multiplex respective rays of the first light, to thereby send out output light; waveguides guide respective rays of the second light toward one end face of the optical device; and light detectors receive respective rays of reflected light that are due to reflection of the respective rays of the second light after being guided by the waveguides, on the one end face or on respective inclined end faces in concave portions formed on that one end face. The light detector is located between the rear-end side of the laser and the one end face or the inclined end face, and the second light is outputted diagonally relative to a perpendicular line with respect to the one end face or the inclined end face.

Optical semiconductor device

A semiconductor laser device includes a semiconductor substrate, a resonator unit formed on the semiconductor substrate and having an active layer, a diffraction grating formed on or underneath the active layer, a front facet of an inverted mesa slope, and a rear facet, an anti-reflection coating film formed on the front facet, a reflective film formed on the rear facet, an upper electrode formed on the resonator unit, and a lower electrode formed underneath the semiconductor substrate, wherein a length in a resonator direction of the resonator unit is shorter than a length in the resonator direction of the semiconductor substrate, and a laser beam is emitted from the front facet.

Semiconductor laser device and method for manufacturing semiconductor laser device

A semiconductor laser () includes an n-type semiconductor substrate (), a stack of an n-type cladding layer (), an active layer (), and a p-type cladding layer () successively stacked on the n-type semiconductor substrate (). An optical waveguide () includes a non-impurity-doped core layer () provided on a light output side of the semiconductor laser () on the n-type semiconductor substrate () and having a larger forbidden band width than the active layer (), and a cladding layer () provided on the core layer () and having a lower carrier concentration than the p-type cladding layer (). The semiconductor laser () includes a carrier injection region (X), and a non-carrier-injection region (X) provided between the carrier injection region (X) and the optical waveguide ().

An edge-emitting semiconductor laser includes: a semiconductor substrate; a first cladding layer having a first refractive index and formed on the semiconductor substrate; an active layer formed on the first cladding layer and having a second refractive index higher than the first refractive index; a Bragg reflector formed on the active layer and in which low-refractive-index layers and high-refractive-index layers each having a thickness larger than &#x3bb;/4n are alternately laid one on another where &#x3bb; is an lasing wavelength and n is a refractive index of a medium; a light absorption layer formed on the Bragg reflector and having bandgap energy lower than that of the active layer; and a second cladding layer formed on the light absorption layer and having a third refractive index lower than the second refractive index.

Edge-emitting semiconductor laser

An optical semiconductor device has a semiconductor laser which emits front-end-surface-side emergent light on the front end surface side and emits rear-end-surface-side emergent light on the rear end surface side, and a mount substrate having the semiconductor laser provided on its front surface. The rear-end-surface-side emergent light is emitted while having an emergence optical axis that extends away from the mount substrate with increase in distance from the rear end surface.

A semiconductor laser according to the present invention comprises a &#x3bb;/2 dielectric film (&#x3bb;:in-medium wavelength of a dielectric film, for example, SiO, SiN, AlO, and AlN) in contact with a facet of a resonator; and a first dielectric double layered film disposed on the dielectric film, which includes a first layer of a-Si and a second layer of a material having a refractive index lower than that of a-Si. The first layer has a thickness &#xbc; of an in-medium wavelength of a-Si, and the second layer has a thickness &#xbc; of an in-medium wavelength of the second layer. Therefore, it is possible to firmly stack the first dielectric double layered film and form a high reflectance film with high yield.

Semiconductor laser device

A semiconductor laser according to the present invention comprises a &#x3bb;/2 dielectric film (&#x3bb;:in-medium wavelength of a dielectric film, for example, SiO, SiN, AlO, and AIN) in contact with an facet of a resonator; and a first dielectric double layered film disposed on the dielectric film, which includes a first layer of a-Si and a second layer of a material having a refractive index lower than that of a-Si. The first layer has a thickness) &#xbc; of a in-medium wavelength of a-Si, and the second layer has a thickness &#xbc; of a in-medium wavelength of the second layer. Therefore, it is possible to firmly stack the first dielectric double layered film and form a high reflectance film with high yield.

A semiconductor laser comprises: a ridge structure including a p-type cladding layer, an active layer, and an n-type cladding layer stacked on one another; and a burying layer burying sides of the ridge structure. The burying layer includes a p-type semiconductor layer and an n-type semiconductor layer that form a pn junction; and one of the p-type semiconductor layer and the n-type semiconductor layer has a carrier concentration of 5&#xd7;10cmor less near the pn junction.

Semiconductor laser

A semiconductor laser includes an active layer on an n-type InP substrate. A diffraction grating and a p-type InP cladding layer are above the active layer. The diffraction grating has at least one phase shift portion. Facets of the distributed feedback laser each have thereon an antireflective film having a reflectance of 3% or less. The diffraction grating does not extend into end regions of the distributed feedback laser, each end region extending 1 &#x3bc;m-20 &#x3bc;m from a respective one of the facets toward an opposite end in a waveguide direction.

Distributed feedback laser diode

A p-type InP buffer layer containing Zn in a low concentration and an undoped InP buffer layer having a carrier concentration of 3&#xd7;10cmor less are stacked on a p-type InP substrate containing Zn. On the undoped InP buffer layer, a Mg-doped p-type InP cladding layer, an InGaAsP optical confinement layer, an InGaAsP MQW active layer, an n-type InGaAsP optical confinement layer, and an n-type InP cladding layer are successively stacked. The diffusion of Zn from the p-type InP substrate into the InGaAsP MQW active layer is suppressed. Moreover, a steep doping profile can be formed in the vicinity of the active layer so that deterioration of device characteristics is suppressed.

In testing a distributed feedback semiconductor laser with a grating having a phase shift part, a spectrum of the distributed feedback semiconductor laser is measured. A difference between an intensity of a side mode at a high-frequency-wave side of a main mode and an intensity of a side mode at a low-frequency-wave side of the main mode is calculated. The distributed feedback semiconductor laser is judged non-defective when the difference is more than a certain value.

Method and device for testing semiconductor laser

A semiconductor laser with a window structure which can emit a light beam with a non-deviated outgoing angle. The semiconductor laser emits a light beam generated at an active layer via a window section. The window section includes a first semiconductor layer having a first carrier concentration and a second semiconductor layer on the first semiconductor layer as an extension of the active layer and which has a second carrier concentration lower than the first carrier concentration. The window section further includes a third semiconductor layer having a third carrier concentration. According to the third layer, a refractive index distribution of the light beam at the window section is symmetrical in the laminating direction, with the extension of the active layer as a center. Because the beam is uniformly propagated, the beam can be emitted without being deviated in the laminating direction.

Semiconductor laser and element for optical communication

A distributed feedback laser device inhibiting beam coupling coefficient variation resulting from fabrication dispersion and improving fabrication yield. The distributed feedback laser device includes cladding layers provided on an InP substrate and located on both sides of an active layer and a diffraction grating having grating bars, different in refractive index from the cladding layers, in either cladding layer and extending in a direction perpendicular to a light emission direction at a prescribed pitch in the emission direction, as well as at least one light distribution control layer, located in the cladding layer, spaced from the diffraction grating and having the same composition as the diffraction grating.

Growing community of inventors

Tokyo, Japan

Yuichiro Okunuki