Nec Corporation

Nec Electronics Corporation

Renesas Electronics Corporation

Shotaro Kitamura

Yasutaka Sakata

Tatsuya Sasaki

Mitsuhiro Kitamura

Keiro Komatsu

Kiichi Hamamoto

Masahide Kobayashi

Disclosed is a distributed feedback semiconductor laser diode device capable of operating at a high output ratio of forward/backward optical power while ensuring satisfactory stability of single-mode oscillation. The distributed feedback semiconductor laser diode device is configured to include a diffraction grating formed in an optical waveguide thereof. In a partial region of the optical waveguide, there is formed an alternately repetitive pattern of a grating part possessing a distributive refractivity characteristic and a no-grating space part possessing a uniform refractivity characteristic. The no-grating space part possessing a uniform refractivity characteristic has an optical path length that is half an integral multiple of a wavelength of laser oscillation, and the grating part possessing a distributive refractivity characteristic includes at least five grating periods.

Semiconductor laser diode device and method of fabrication thereof

An improved throughput can be presented, since an influence of the deterioration in crystallinity created in the epitaxial layer can be eliminated by a simple and easy method, and a semiconductor laser device having stabilized properties such as threshold current, slope efficiency, device life time and the like can be presented. A method for manufacturing a semiconductor laser device according to the present invention comprises: forming partially a diffraction grating on a surface of a semiconductor substrate or on a film on the surface of the semiconductor substrate; and forming a multiple-layered film by forming an epitaxial layer on a surface of the diffraction grating. The operation of forming the diffraction grating includes an operation of forming the diffraction grating so that a width of the diffraction grating in a direction that is orthogonal to a cavity direction of the semiconductor laser device is presented as a width equal to or longer than a sum of a mesa width and 30 &#x3bc;m.

Method for manufacturing semiconductor laser device and semiconductor laser device

A distributed feedback laser diode comprises a phase-shifting portion in diffraction gratings. The magnitude of a phase shift in the phase-shifting portion is 8&#x39b;/40 to 9&#x39b;/40, &#x39b; representing twice the distance between the diffraction gratings. A main mode stands on a lower wavelength side than the center of a stop band when an injected current is of a level of a threshold current, whereas the main mode is shifted to the center of the stop band and a sub mode is suppressed from growing when the injected current is of a level of an operating current.

Distributed feedback laser diode

The invention provides a semiconductor optical amplification element which reduces noise light emission and increases saturation output power. The semiconductor optical amplification element has an optical waveguide which includes a core layer formed from an active layer acting as an optical amplification medium and amplifies and outputs an optical signal without electrically converting. The light reflection factor on an inputting side end of the element for the optical signal is lower than the light reflection factor on another outputting side end of the element.

Semiconductor optical amplification element

A semiconductor optical amplifier which has a good extinction ratio and a simple structure includes an optical waveguide having at least a curved portion. The optical waveguide has light input and output ends offset from each other to keep optical fibers out of alignment with each other at respective opposite ends of the optical waveguide.

Semiconductor optical amplifier

A semiconductor optical monolithic integration device has a semiconductor substrate including an active region and a passive region. Epitaxial layers including a multiple quantum well structure have a variation in band gap energy and thickness along a waveguide direction. The epitaxial layers in the active region are selectively grown by a metal organic vapor phase epitaxy on a first selective growth area defined by a first mask pattern provided in the active region except in the passive region. The first mask pattern has a variation in width along the waveguide direction. The epitaxial layers are simultaneously and non-selectively grown on an entire surface of the passive region by the metal organic vapor phase epitaxy and the epitaxial layers have a mesa structure in the active region and a plane structure in the passive region. A cladding layer having a ridged structure is selectively grown by a metal organic vapor phase epitaxy on a second selective growth area defined by a second mask pattern provided in the active and passive regions. The second mask pattern has a constant width. In the active region, the ridged cladding layer completely embeds the mesa structure epitaxial layers and in the passive region the ridged cladding layer are provided on the plane structure epitaxial layers.

Semiconductor optical integrated circuits and method for fabricating the

A semiconductor optical monolithic integration device comprises a semiconductor substrate including an active region and a passive region. Epitaxial layers including a multiple quantum well structure have a variation in band gap energy and thickness along a waveguide direction. The epitaxial layers in the active region are selectively grown by a metal organic vapor phase epitaxy on a first selective growth area defined by a first mask pattern provided in the active region except in the passive region. The first mask pattern has a variation in width along the waveguide direction. The epitaxial layers are simultaneously and non-selectively grown on the entirety of the passive region by metal organic vapor phase epitaxy and epitaxial layers having a mesa structure in the active region and a plane structure in the passive region are formed. A cladding layer having a ridged structure is selectively grown by a metal organic vapor phase epitaxy on a second selective growth area defined by a second mask pattern provided in both the active and passive regions. The second mask pattern has a constant width. In the active region the ridged cladding layer completely embeds the mesa structure epitaxial layers and in the passive region the ridged cladding layer is provided on the plane structure epitaxial layers.

Semiconductor optical integrated circuits

In a method of manufacturing an optical semiconductor element including at least the steps of forming a mask having a stripe-like gap or interval on a semiconductor substrate, epitaxially growing a semiconductor ridge including an active layer on only an exposed gap portion of the semiconductor substrate, and epitaxially growing a semiconductor cladding layer to cover the ridge, the thickness of the active layer is substantially the same as the width of the active layer.

Growing community of inventors

Tokyo, Japan

Shotaro Kitamura