Rohm Co., Ltd.

Masayoshi Ashida

Satoshi Uchida

A group of semiconductor layers of a first light emitting region( ) including an active layer( ), determined by a first wavelength of laser beam, sandwiched between two cladding layers( ) and( ) of which the band gap is greater than that of the active layer( ) are deposited on a semiconductor substrate . Similarly, another group of semiconductor layers of a second light emitting region( ) including an active layer( ), determined by a second wavelength of laser beam, sandwiched between two cladding layers( ) and( ) of which the band gap is greater than that of the active layer are deposited via a contact layer( ) on the first light emitting region( ). The first and the second light emitting region( ) and ( ) are aligned with each other along the perpendicular (vertical) to the semiconductor substrate( ). Accordingly, a multi-color semiconductor laser having multiple laser beam sources in their respective light emitting regions aligned along the vertical to the substrate can be fabricated by simple steps of production.

Semiconductor laser and method for manufacturing the same

A semiconductor laser element is made by forming a lower clad layer, an active layer and an upper clad layer sequentially one on top of another on a semiconductor substrate, forming an etching stop layer completely over the upper clad layer, forming a contact layer on the etching stop layer, and etching portions of the contact layer to form steps. The etching stop layer has a slower etching speed than the contact layer against the etching liquid used for forming the steps by etching portions of the contact layer. An upper electrode is formed on the contact layer and a lower electrode is formed on the bottom surface of the substrate. The steps provide areas in the active layer where a current will not flow through.

Semiconductor laser elements and method of making same

A semiconductor laser device is of a double-hetero structure having an active layer sandwiched between a first conductivity type cladding layer and a second conductivity type cladding layer, one of the first and second conductivity type cladding layers being formed by a first cladding layer and a second cladding layer. A current blocking layer is provided between the first cladding layer and the second cladding layer, and formed of a material having a forbidden band gap wider than that of the active layer and a refractive index lower than that of the one cladding layer, the current blocking layer being formed with a current injecting region having a conductivity type different from that of the one cladding layer. An over-saturation absorbing layer is formed in the current blocking layer, the over-saturation absorbing layer is formed of such a material that has approximately the same forbidden band gap as that of the active layer. It is possible to set independently the distance between the active layer and the over-saturation absorbing layer as well as the distance between the active layer and the current blocking layer, so as to provide device operation on a low operating current (lowered threshold value) with low noise and astigmatism in a multi mode instead of a longitudinal mode.

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Kyoto, Japan

Masayoshi Ashida