| 摘要 |
PURPOSE:To perform light emission in two wavelength bands by means of a single element, to make the position emitting the light the same in the respective wavelength bands and to greatly simplify the structure of the element by a method wherein a first active layer and a second one are made to emit light according to their respective wavelengths, and a waveguide layer is used as a common resonator to the light of the respective wavelengths. CONSTITUTION:This semiconductor laser possesses a first active layer 3 (1.5mum) which is provided on one side on a substrate 1 or a buffer layer BF, a second active layer 4 which is provided on the other side on the substrate 1 or the buffer layer BF and on the upper surface of the first active layer 3 and has a band gap wavelength shorter shorter than that of the first active layer 3, a waveguide layer 5 which is provided on the upper surface of this second active layer 4 and has a band gap wavelength shorter than those of the first and second active layers, a clad layer 6 which is provided on the upper surface of this waveguide layer 5 and electrodes 7 and 8 for selectively performing current injection in the first and second active layers through the substrate 1 and the clad layer 6. When a current is passed through between an entire surface electrode 2 and the electrode 8, a light of a wavelength of 1.5mum is generated from the first active layer 3. In this case, a light generated in a certain wavelength is absorbed in a medium which has the same wavelength as that of the light and is in a nonexcitation state if there exists this medium, the light generated is waveguided to the second active layer 2 (1.3mum) and the waveguide layer 5 (1.1-1.2mum), resonated in a Fabry-Perot mode and a laser oscillation of the laser light of a wavelength of 1.5mum is performed.
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