The Furukawa Electric Co., Ltd.

Kazuaki Nishikata

Michinori Irikawa

Norihiro Iwai

Akihiko Kasukawa

Hitoshi Shimizu

Junji Yoshida

Takehiko Nomura

Noriyuki Yokouchi

Maiko Ariga

Takeo Kageyama

Takeharu Yamaguchi

Toru Fukushima

Koji Hiraiwa

Yoshiyuki Hirayama

Yuji Hiratani

A surface emitting laser element array comprises a plurality of surface emitting laser elements () on a same substrate () each comprising a mesa post formed of a laminated structure including an active layer () for reducing a crosstalk between the surface emitting laser elements constituting the surface emitting laser element array, and for improving a high speed response, wherein each of the surface emitting laser elements () comprises a first electrode (), a second electrode () and a third electrode () that have a polarity different from that of the first electrode (); the first electrode () is arranged on the mesa post; the second electrode () is arranged on one surface of the substrate () same as that of the first electrode (); the third electrode () is arranged on the other surface of the substrate () opposite to that of the first electrode and the second electrode () and is provided as a common electrode of the surface emitting laser elements (); and an electric current is applied to the active layer () using the first electrode () and the second electrode ().

Surface emitting laser element array

A method for manufacturing a semiconductor optical waveguide comprises the steps of forming a core layer having an Al content which monotonically increases from the central part thereof to the film surface, and selectively oxidizing the core layer to obtain a peripheral, oxidized region and a central, non-oxidized region acting as a waveguide. The waveguide is tapered to have a circular mode field at the distal end thereof for efficiently coupling with an optical fiber.

Semiconductor optical waveguide structure

Semiconductor optical waveguide

A semiconductor waveguide type photo detector capable of preventing leak current from occurring and excellent in dark current characteristics, and a manufacturing method thereof are provided. In a semiconductor waveguide type photo detector, a layered structure is formed on a semiconductor substrate, the layered structure formed by building a first semiconductor layer, a second semiconductor layer and a third semiconductor layer in due order, the first semiconductor layer being of one of p type and n type, the second semiconductor layer having lower band gap energy than that of the first semiconductor layer, the third semiconductor layer having higher band gap energy than that of the second semiconductor layer and having a conductive type opposite to that of the first semiconductor layer, and wherein at least the second semiconductor layer of the layered structure has a semiconductor waveguide having a mesa stripe structure, and at least a side surface and/or a light incidence end face of the second semiconductor layer is curved.

Semiconductor waveguide type photodetector and method for manufacturing the same

A waveguide-type variable-sensitivity semiconductor photodetector has a waveguide photodetector area and an optical attenuation area formed on an n-InP substrate. The optical attenuation area includes a GaInAs optical waveguide layer having a bandgap energy of 0.85 eV, a pair of upper and lower cladding layers each having a bandgap energy of 1.35 eV and an intermediate layer disposed at the heterojunction interface between the optical waveguide layer and the upper cladding layer and having a bandgap energy of 1.0 eV. A pile-up of halls at the heterojunction interface is prevented by the intermediate layer to improve the linearity of the output optical signal to the input optical signal.

Waveguide-type variable-sensitivity semiconductor photodetector

An optical waveguide type photodiode has a plurality of semiconductor layers formed one upon another on a semiconductor substrate and including an optical absorption layer sandwiched between a pair of optical confinement layers for guiding incident light in parallel with the semiconductor layers, wherein a light absorption quantity per unit length of an optical waveguide area constituted by the optical absorption layer is substantially constant throughout the entire area thereof. Specifically, the optical confinement factor .GAMMA.(x) of the optical waveguide area is set so as to increase with guided distance x of light. Preferably, a device structure is employed in which the thickness d(x) of the optical absorption layer increases with the guided distance x of light. Also, the optical absorption layer is formed by selective area growth with the use of a pair of selective area growth masks, and these masks have a mask pattern such that the mask width thereof gradually decreases/increases in the light guiding direction, whereby a photodiode with the above device structure can be fabricated with ease.

Optical waveguide type photodiode and a process of producing the same

A waveguide type semiconductor photodetector comprises a n-InP substrate, and a laminate including a first and second optical confinement layers and an undoped optical absorption layer interposed therebetween. The optical absorption layer has a thickness between 0.2 and 0.5 .mu.m, and a bandgap wavelength smaller than the bandgap wavelength of the first and second optical confinement layers. The photodetector has a large mode field diameter and a small coupling loss between the same and a glass fiber.

Waveguide type semiconductor photodetector

Waveguide type light receiving element

The present invention provides a semiconductive light-emitting device involving a light-emitting layer of the multilayer strained quantum well structure that has a plurality of quantum well layers and a plurality of barrier layers, where each of said quantum well layers is constituted of a semiconductive crystal subjected to intraplanar compressive strain; each of the barrier layers is constituted of semiconductor crystal of AlInAs, AlGaInAs or AlGaInAsP. For high differential gain, each quantum well layer is 6nm thick or less, and the summed quantum well layers measure 13 to 1000 nm in thickness. Likewise, the invented scheme produces a light-emitting device involving a light-emitting layer of the multilayer strain compensation quantum well structure that has a plurality of quantum well layers and a plurality of barrier layers, where each of said quantum well layers is constituted of a semiconductive crystal subjected to intraplanar compressive strain; each of the barrier layers is constituted of semiconductor crystal of AlInAs, AlGaInAs or AlGaInAsP. For high differential gain, each quantum well layer is 6nm thick or less, and the summed quantum well layers measure 13 to 1000 nm in thickness.

Semiconductive light-emitting device having strained MQW with AlGaInAs

A photo diode in which an optical absorption layer and a p-type semiconductor layer neighboring on each other are designed to be at almost the same valence band level (their offset not exceeding 0.05 eV). Preferably the optical absorption layer is a GaInAsP layer with an absorption edge wavelength of 1.65 to 1.55 .mu.m, and the p-type semiconductor layer and lattice-matching with the preceding semiconductor layer are each an AlGaInAs layer with an absorption edge wavelength of 1.55 to 1.30 .mu.m remaining shorter than that of the optical absorption layer.

Photo diode providing high-linearity signal current in response to light

Strained superlattice semiconductor photodetector having a side contact

There is provide a method of manufacturing a compound semiconductor (MBE) that can make the substrate surface of the semiconductor highly clean and plane so that no impurity may be left between the substrate surface and the grown crystal layer. In the step of cleaning a substrate with MBE, the substrate surface is irradiated with V molecular beams that cannot be significantly deposited out of molecular beams to be used for the crystal growth step, said V molecular beams being irradiated under a condition of P.sub.1 .ltoreq.(P.sub.2 .times.1/2), where P.sub.1 is the pressure of V molecular beams and P.sub.2 is the pressure of molecular beams in the crystal growth step and the temperature of the substrate surface is raised by heating until stabilized group III surfaces appear on the substrate surface. A very cleanand smooth substrate surface can be obtained with such an arrangement. Harmful impurities can be completely eliminated from the interface of the substrate and the crystal. The formation of a buffer layer can be effectively prevented in the initial stages of crystal growth. In short, high-quality compound semiconductors can be produced on a reliable basis.

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Tokyo, Japan

Kazuaki Nishikata