Mitsubishi Electric Corporation

Yohei Hokama

Koichi Akiyama

Satoshi Nishikawa

Yosuke Suzuki

Yuichiro Horiguchi

Toshiyuki Tanaka

Shusaku Hayashi

Kentaro Enoki

Keigo Fukunaga

A semiconductor laser in which a PD unit monitoring an optical output is integrated is provided. A semiconductor laser () includes: a DFB unit including a back surface side first cladding layer (), a first diffraction grating layer (), a light emitting layer () having a first MQW structure and emitting a laser beam, a front surface side first cladding layer (), and a first contact layer () which are stacked; a DBR unit including a back surface side second cladding layer () having a resistivity higher than that of the back surface side first cladding layer (), a second diffraction grating layer () reflecting part of the laser beam toward the DFB unit, a first core layer () guiding a remnant of the laser beam and having an effective bandgap energy smaller than that of the first MQW structure, and a front surface side second cladding layer () having a resistivity higher than that of the front surface side first cladding layer () which are stacked; and a PD unit including a back surface side third cladding layer (), a second core layer () having a second MQW structure absorbing the remnant of the laser beam guided by the first core layer (), a front surface side third cladding layer (), and a second contact layer () which are stacked.

Semiconductor laser, semiconductor laser array and method of manufacturing semiconductor laser

An optical semiconductor device includes a semiconductor substrate, a first semiconductor layer provided on the semiconductor substrate, and a mesa waveguide provided on the principal surface of the first semiconductor layer. The semiconductor device also includes a buried layer covering the upper surface of the first semiconductor layer. Part of the upper surface of the first semiconductor layer is exposed. A mesa structure provided at the boundary between a part of the first semiconductor layer is covered with the buried layer and a part of the first semiconductor layer is exposed. One side of the mesa structure is covered with the buried layer, and the other side is exposed. The optical semiconductor device can reduce the generation of stress in the buried layer, for example, to suppress the occurrence of cracks in the buried layer and enhance the reliability.

Optical semiconductor device and method for manufacturing the same

The object is to provide a technology capable of efficiently injecting a current into a core layer of a buried waveguide. On one end side of the substrate, a buried waveguide including a core layer, a cladding layer, and a current blocking layer is disposed, both sides of the core layer in a layer-stacking direction are sandwiched by the cladding layer, and both sides of the core layer in a width direction that is perpendicular to the layer-stacking direction are sandwiched by the current blocking layer. On another end side of the substrate, a ridge waveguide including the core layer and the cladding layer is disposed, and both sides of the core layer in the layer-stacking direction are sandwiched by the cladding layer.

Semiconductor optical waveguide and optical integrated element

An optical modulator element includes first and second optical modulators, an optical input terminal, and a branch coupler. Each of the first and second optical modulators includes a pair of Mach-Zehnder waveguides, a first optical coupler to split rays from the branch coupler into the pair of Mach-Zehnder waveguides, and a second optical coupler to combine rays transmitted through the pair of Mach-Zehnder waveguides. The first and second optical modulators are disposed in such a manner that a traveling direction of rays propagating through the pair of Mach-Zehnder waveguides of the first optical modulator and a traveling direction of rays propagating through the pair of Mach-Zehnder waveguides of the second optical modulator are angled toward each other.

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Tokyo, Japan

Yohei Hokama