| 摘要 |
PROBLEM TO BE SOLVED: To output laser beam with high modulation characteristics. SOLUTION: The wavelength variable type semiconductor laser 27 has an n-type semiconductor substrate 11, an active layer 17 which is arranged above the n-type semiconductor substrate and produces light, a p-type clad layer 22 arranged above the active layer, and a diffraction grating (15) which selectively oscillates a specific wavelength alone among light produced by the active layer. In the laser 27, an element length L which shows the length in the propagation direction of light produced in the active layer is set at 200 to 500μm. The p-type clad layer 22 comprises a low concentration clad layer 19 with low impurity concentration, and a high concentration clad layer 20 with high impurity concentration which are arranged one by one from the active layer side. COPYRIGHT: (C)2005,JPO&NCIPI
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