| 摘要 |
PURPOSE:To obtain a variable wavelength semiconductor laser which performs effectively the current concentration on an optical waveguide layer by reducing a damage to an active layer. CONSTITUTION:A ridge-waveguide type distributed feedback semiconductor laser is constituted in the way that diffracted lattices 12 are formed inside an optical waveguide layer 7 or its neighborhood, and an active layer 3 having less than de Broglie optical wavelength is formed between the optical waveguide layer 7 and a substrate 1. Electrodes 6, 9, 11 are provided so that they can control independently the current injection to the optical waveguide 7 or impression of electrical field, and also control the current injection to the active layer 3. Mesa etching for forming the ridge waveguide is applied to the area near to the optical waveguide layer 7, or application of mesa etching stops at least at the point of getting to the inner part of the optical waveguide layer 7. |
