The Furukawa Electric Co., Ltd.

Toshikazu Mukaihara

Akihiko Kasukawa

Tatsuya Kimoto

Takeharu Yamaguchi

Satoshi Arakawa

Hiroyuki Kobayashi

Hitoshi Shimizu

Masaki Funabashi

Noriyuki Yokouchi

Takuya Ishikawa

Maiko Ariga

Tatsuhiko Ueki

Hiroshi Takano

Nobumitsu Yamanaka

Go Kobayashi

Mamoru Shimada

Mizuki Oike

Yuji Hiratani

Kengo Muranushi

Sayoko Ibe

Integrated are: semiconductor lasers of distributed feedback type that oscillate in single mode at emission wavelengths different from one another; a coupler that has as many input ports as the semiconductor lasers, the input ports to which output light from the semiconductor lasers are input, the coupler guiding and outputting the output light; and an amplifier that amplifies the output light from the coupler, and a predetermined relation holds true, where 'N' is the number of the semiconductor lasers, 'Ldfb' is a cavity length of each of the semiconductor lasers, &#x201c;&#x394;&#x3bd;&#x201d; is a spectral linewidth of laser light output therefrom, &#x201c;Lsoa&#x201d; is an amplifier length of the amplifier, &#x201c;A&#x201d; is an amplification factor of the amplifier, &#x201c;&#x394;&#x3bd;&#x201d; is a spectral linewidth of amplified laser light output therefrom, and &#x201c;R&#x201d; is &#x394;&#x3bd;/&#x394;&#x3bd;

Integrated semiconductor laser element

An integrated semiconductor laser element includes: semiconductor lasers that oscillate at different oscillation wavelengths from one another, each laser oscillating in a single mode; an optical coupler; and a semiconductor optical amplifier. At least one of active layers of the semiconductor lasers and an active layer of the semiconductor optical amplifier have a same thickness and a same composition that is set to have a gain peak wavelength near a center of a wavelength band formed by the oscillation wavelengths. The semiconductor optical amplifier includes: an equal width portion formed on a side of the optical coupler to guide light in a single mode; and an expanded width portion formed on a light output side. The width of the expanded width portion is set according to a total thickness of well layers of the active layer of the semiconductor optical amplifier.

Integrated semiconductor laser element, semiconductor laser module, and optical transmission system

An optical modulehas a laser light source, optical branching meansfor receiving laser light from the laser light source, making a part of the laser light pass through the optical branching means and branching a remaining part of the laser light; a photodetecting portionP receiving the remaining part of the laser light branched from the optical branching meansand a packageholding therein the laser light source, the optical branching meansand the photodetecting portionP, the packagehaving stray light reducing meansandprovided therein to reduce stray light generated inside the package.

Optical module

An optical module including a temperature measurement module and an optical part having a temperature dependency. The module includes a temperature control part mounted directly or indirectly on the optical part and the temperature measurement part for controlling a temperature of the optical part and the measurement part by thermal contact. An adjustment system is also provided for adjusting a difference of the temperature of the optical part and the measurement part by controlling the heat flow into/out of the optical part or the measurement part.

Optical transmission module with temperature control

A semiconductor laser device according to the present invention comprises a laminated structure of a semiconductor material including an active layer formed of a quantum well structure, a low-reflection film formed on one end face of the structure, and a high-reflection film formed on the other end face of the structure. The cavity length (L) of the device is 1,200 &mgr;m or more. This laser device, which enjoys high kink currents and a satisfactorily linear current-optical output characteristic, is a useful pumping light source for optical fiber amplifier.

Semiconductor laser device

A semiconductor laser device ( ) includes a layered structure formed on an n-type GaAs substrate ( ) having a bandgap energy Eg and including an n-type AlGaAs cladding layer ( ), an active layer ( ) including a quantum-well structure of two layers InGaAs/GaAs having a bandgap energy Eg which is smaller than Eg , a p-type AlGaAs cladding layer ( ), and a p-type GaAs cap layer ( ), which are consecutively epitaxially grown. The cap layer and the upper portion of the p-type cladding layer are formed as a stripe-shaped mesa structure. An SiN passivation film ( ) is formed on the areas except for the top of the cap layer. On the exposed cap layer and the passivation layer a p-side electrode ( ) is formed. On the bottom surface of the substrate an n-side electrode ( ) including layered metal films of In/AuGe/Ni/Au is formed. An absorption medium layer is interposed between the GaAs substrate and the n-side electrode.

Semiconductor laser

A surface-emitting semiconductor laser device having reduced device resistance, a method for fabricating the device and a surface-emitting semiconductor laser array employing the device are provided. The laser device comprises a lower reflector layer structure and an upper reflector layer structure, formed on a p-type semiconductor substrate. An etching blocking layer, a current confinement layer, and an active layer are formed in that order from below between the lower and upper reflector layer structures. The portion over the etching blocking layer is formed into a mesa shape.

Surface-emitting semiconductor laser device and method for fabricating the same, and surface-emitting semiconductor laser array employing the laser device

A semiconductor light emitting device including a semiconductor substrate and an active layer having band gap energy smaller than that of the active layer, and the bottom surface of the semiconductor substrate opposite to the active layer is a photo diffused reflection surface having unevenness. The unevenness reduces an amount of reflection rays to enable the stable operation.

Semiconductor light emitting device

Disclosed is a process of producing a semiconductor layer structure which emits lights with a plurality of luminescence wavelengths from the same quantum well structure. The layer structure has a layer structure which has the quantum well structure located between a lower light-confinement layer and an upper light-confinement layer. At least a part of the quantum well structure is an area which has a shorter luminescence wavelength than those of the other portions. This area is produced by stacking a lower cladding layer, the lower light-confinement layer, the quantum well structure, the upper light-confinement layer and a first semiconductor layer having a first conductivity type on a semiconductor substrate by epitaxial growth and further stacking a second semiconductor layer having the opposite conductivity type to that of the first semiconductor layer on the entire surface or a partial surface of the first semiconductor layer. This second semiconductor layer may be removed after the formation.

Process of producing semiconductor layer structure

A DFB semiconductor laser device including: a semiconductor substrate; and an active layer and a diffraction grating overlying the semiconductor substrate, the diffraction grating having a composition of GaInNAs(Sb) and absorbing light having a laser emission wavelength of the active layer. The DFB semiconductor laser device having a higher SMSR can be provided which stably operates in a wider range of injection current by proving the diffraction grating formed by the GaInNAs(Sb) having the composition for efficiently absorbing light which has the laser emission wavelength of the active layer.

Distributed feedback semiconductor laser device

A semiconductor light emitting diode (,) is formed on an n-type GaAs substrate and includes: an AlGaInP based double heterojunction structure in which an active layer (,) is sandwiched between cladding layers (,); an upper P-type contact layer,and a ring-shaped upper electrode (,) having an opening (,), wherein light is emitted through the upper p-type contact layer (,) and the opening (,) of the upper electrode (,). The upper p-type contact layer (,) is a semiconductor layer made of AlGaAs or AlGaAsP having an Al content of 0.5 or more, and doped with impurities at a carrier concentration of 5&times;10,cm,or more. The semiconductor light emitting diode emits light in a desired emission pattern and at higher intensities, and is capable of being fabricated by relatively simple processes.

Semiconductor light-emitting diode

A reflection multilayer including low-refraction layers and semiconductor layers is formed on the facets of a semiconductor laser. The bandgap energy (Ewg) of a waveguide layer of the reflection multilayer is greater than the bandgap energy (Eac) of an active layer of the semiconductor laser (Eac&lt;Ewg), while the thickness (Twg) of the former is smaller than the thickness (Tac) of the latter (Tac&gt;Twg). Further, a photodetector and an optical modulator are formed on the semiconductor laser with the reflection multilayer thereon by butt-Jointing or monolithically by selective vapor growth with use of selective growth masks. Relations Ewg&gt;Emod&gt;Eac&gt;Epd and Twg&gt;Tmod&gt;Tac&gt;Tpd are established between the respective bandgap energies and thicknesses of individual layers, whereby the absorption rate of the reflector waveguide layer and diffraction loss are lowered or reduced, and the rates of optical absorption in an optical absorption layer of the photodetector are increased.

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Tokyo, Japan

Toshikazu Mukaihara