Nec Corporation

Takemasa Tamanuki

Hiroyuki Yamazaki

Tatsuya Sasaki

Mitsuhiro Kitamura

The semiconductor laser disclosed includes a first conductivity type buffer layer, an active layer and a second conductivity type cladding layer which are sequentially positioned on a first conductivity type semiconductor substrate. The active layer has a laser gain region to which an electric current is injected. The laser gain region having a width varying linearly along a resonating direction is disposed between a high reflection film provided on a facet of a wide side of the laser gain region of the active layer and a low reflection film provided on a facet of a narrow side of the laser gain region of the active layer. The facet of the narrow side is for outputting oscillation beams of a high order mode. This provides a high electrical-to-optical conversion efficiency, and enables the outputting of a large output from a narrow light emission region.

Semiconductor laser with wide side of tapered light gain region

In a semiconductor optical amplifier device comprising a semiconductor laser section and a semiconductor optical amplifier both of which are formed on the same semiconductor substrate and which are coupled to each other, the semiconductor optical amplifier comprises a tapered electrode formed on an upper surface thereof. The tapered electrode is divided into a plurality of divided electrodes by at least one of dividing sections which extends along a propagation direction of an incident laser beam. The plurality of divided electrodes are supplied with injection currents which are variable in each of the plurality of divided electrodes.

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Tokyo, Japan

Takemasa Tamanuki