Mitsubishi Electric Corporation

Mitsubishi Denki Kabushiki Kaisha

Go Sakaino

Naoki Nakamura

Yuichiro Okunuki

Ayumi Fuchida

Toshitaka Aoyagi

Tetsuya Uetsuji

Masaaki Shimada

Tohru Takiguchi

Yasuaki Yoshida

Minoru Kawano

Katsuhiko Goto

Yoshihiro Hisa

Yosuke Suzuki

Naoki Kosaka

Tadashi Takase

Ryoko Suzuki

Hideki Haneda

A semiconductor laser device comprises a stem serving as a base; a laser diode LD submount having surface electrodes arranged thereon and joined to the surface of the stem; an LD chip joined to the surface electrode and connected with the surface electrode; and leads fixed in through holes formed in the stem by means of sealing parts and electrically connected to the surface electrodes via embedded layers in via holes formed in the LD submount, wherein grooves are formed in portions of the sealing parts or in portions of the LD submount around the connections between the leads and the embedded layers, to obtain a good modulated light waveform.

Semiconductor laser device

What is provided are: an active-layer ridge which is composed of an n-type cladding layer, an active layer, a first p-type cladding layer and a second n-type blocking layer that are stacked in this order on an n-type InP substrate, and which is formed to project from a position lower than the active layer; burying layers by which both side portions of the active-layer ridge are buried up to a position higher than the active layer; first n-type blocking layers which are each stacked on a front-surface side of each of the burying layers, to be placed on the both sides of the ridge; and a second p-type cladding layer by which an end portion of the active-layer ridge and the first n-type blocking layers are buried thereunder; wherein a current narrowing window for allowing a hole current to pass therethrough is provided in and at a center of the second n-type blocking layer placed at a top of the active-layer ridge.

Semiconductor laser and method for manufacturing same

A semiconductor optical device is provided with a semiconductor substrate that has a length and width, a laser section that is provided on the semiconductor substrate and includes an active layer and an optical waveguide section that is provided adjacent to the laser section on the semiconductor substrate and is joined to the laser section. The optical waveguide section includes a core layer that is connected to an end portion of the active layer, and a pair of cladding layers between which the core layer is sandwiched and emits, from an emission end surface, light incident from the joining interface between the optical waveguide section and the laser section. The semiconductor optical device may be also provided with a reflection suppression layer that is provided on the upper surface of the optical waveguide section.

Semiconductor optical 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 ().

Optical semiconductor device

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.

An upper cladding layer includes a first low carrier concentration layer having a lower carrier concentration than the p-type cladding layer and a first Fe-doped semiconductor layer formed on the first low carrier concentration layer. The leakage current suppression layer includes a second Fe-doped semiconductor layer disposed on a side of the p-type semiconductor layer. The first low carrier concentration layer has a side wall part that is in contact with a side face of the p-type cladding layer. The first Fe-doped semiconductor layer is disposed on a side of the p-type cladding layer via the side wall part of the first low carrier concentration layer and is not in contact with the p-type cladding layer.

An optical semiconductor device includes: a mesa stripe structure including an n-type cladding layer, an active layer, and a p-type cladding layer laid one on another; and a buried layer buried on opposite sides of the mesa stripe structure, wherein the active layer is a multiple quantum well structure having well layers and carbon-doped barrier layers, the buried layer includes a p-type semiconductor layer and an Fe-doped or Ru-doped high-resistance semiconductor layer laid one on another, side surfaces of the n-type cladding layer are covered with the p-type semiconductor layer and are not contiguous with the high-resistance semiconductor layer, and side surfaces of the active layer are not contiguous with the p-type semiconductor layer.

A semiconductor optical element and an integrated semiconductor optical element suppressing leakage current flow through a burying layer. A mesa-stripe-shaped laminate structure includes a p-type cladding layer, an active layer, and an n-type cladding layer. A burying layer on a side of the laminated structure includes, a first p-type semiconductor layer, a first n-type semiconductor layer, an Fe-doped semiconductor layer, a second n-type semiconductor layer, a low carrier concentration semiconductor layer, and a second p-type semiconductor layer. The Fe-doped semiconductor layer is not grown on a (111)B surface of the first p-type semiconductor layer and of the first n-type semiconductor layer. The second n-type semiconductor layer is not grown on a (111)B surface of the first p-type semiconductor layer, of the first n-type semiconductor layer, and of the Fe-doped semiconductor layer.

Semiconductor optical element and integrated semiconductor optical element

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 method for manufacturing a semiconductor optical device comprises: forming a groove on a first semiconductor layer; forming a second semiconductor layer containing aluminum in the groove; forming a third semiconductor layer on the first semiconductor layer and the second semiconductor layer; forming an insulating layer on the third semiconductor layer covering the region opposite the second semiconductor layer; forming a stripe-shaped structure by etching the first semiconductor layer and the third semiconductor layer without exposing the second semiconductor layer, using the insulating layer as a mask; and burying the stripe-shaped structure with burying layers.

Method for manufacturing semiconductor optical device

A semiconductor optical device which has a ridge structure includes a waveguide area between paired mesa trenches; first and second mount areas disposed outside the mesa trenches; a first spacer layer disposed in a first mount area and a second spacer layer disposed in a second mount area; a first metal layer electrically connected to an upper cladding layer in the waveguide area and extending from the waveguide area over the first mount area; and a second metal layer disposed over the second mount area. Thicknesses from a back surface of the semiconductor optical device to the first metal layer in the first mount area and to the second metal layer in the second mount area are both larger than thickness from the back surface to the first metal layer in the waveguide area.

An n-InP second upper cladding layer is laid on a p-InP lower cladding layer while an active layer having upper and lower boundary surfaces that are uniformly flat in an optical waveguide direction is interposed therebetween. A diffraction layer having a phase-shifted structure in the optical waveguide direction is interposed between the lower cladding layer and the active layer or between the second upper cladding layer and the active layer. The length L of the diffraction grating layer in the direction of the optical waveguide is L&lE;260 &mgr;m; a mean coupling factor &kgr; of a diffraction grating layer is &kgr;&gE;150 cm ; and &kgr;L satisfies 5.6>&kgr;L>3.0.

An optical module includes a substrate having an upper surface and a groove on the upper surface; an optical fiber having a core and an end facet, disposed in the groove of the substrate; an optical semiconductor device having an upper surface and a light interactive area on the upper surface optically coupled to the optical fiber; and a block having a side surface on which the optical semiconductor device is fixed and a lower surface perpendicular to the side surface. The optical semiconductor device is fixed onto the side surface of the block so that the distance from the light interactive area to the lower surface of the block is equal to the distance from the core of the optical fiber to the upper surface of the substrate; and the block is disposed on the substrate, with the lower surface contacting the upper surface of the substrate, so that the light interactive area is opposed to the end facet of the optical fiber. The core of the optical fiber and the light interactive area are accurately aligned with the surface of the substrate as a reference regardless of the thickness of the substrate, resulting in a high coupling efficiency between the optical fiber and the optical semiconductor device.

Optical module and method of fabricating optical module

In a semiconductor laser device including a stack of semiconductor laser chips, each semiconductor laser chip includes opposite upper and lower surfaces, an upper electrode disposed on a portion of the upper surface, and a lower electrode disposed on a portion of the lower surface. Two adjacent semiconductor laser chips in the stack are connected such that the lower electrode of an upper laser chip is bonded to the upper electrode of a lower laser chip with solder. Since the upper electrode (lower electrode) is disposed on a portion of the upper surface (lower surface) of each laser chip, i.e., it is not disposed over the entire upper surface (lower surface) of the laser chip, the solder hardly flows over the side surface of the laser chip, so that unwanted short-circuiting between the upper electrode and the lower electrode of the laser chip is avoided. In addition, when solder is molten between two electrodes, the molten solder spreads over the surfaces of the electrodes, and the surface tension of the molten solder draws the electrodes to each other so that the electrodes are automatically aligned with each other. Therefore, in this stacked laser device, since the surface tension of the molten solder functions between the upper electrode and the lower electrode of the adjacent laser chips, automatic alignment is performed between these laser chips.

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Tokyo, Japan

Go Sakaino