| 摘要 |
PROBLEM TO BE SOLVED: To provide a distributed feedback semiconductor laser element of high single mode yield, low oscillating threshold current and high quantum efficiency. SOLUTION: In a distributed feedback semiconductor laser element that contains a layer structure, wherein a light absorption layer 9 of diffraction grating structure is formed above or below an active layer 4, an equivalent absorption coefficient of the light absorption layer 9 is large in a center part R1 of a resonator, and is small in the vicinity of an end surface R2 thereof. More specifically, the light absorption layer 9 is composed of the same semiconductor material, and its thickness is large at the center part R1 of the resonator, becomes thinner the nearer it gets to the vicinity of end surface R2 thereof.
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