| 摘要 |
PROBLEM TO BE SOLVED: To provide a distributed feedback semiconductor laser which improves the light output ratio of the front and the back of an element, while maintaining a proper single-axis mode yield. SOLUTION: The distributed feedback semiconductor comprises a diffraction grating structure 4 having a phase shift part, a guide layer 3 having the diffraction grating structure 4 in an embedded state, and an active layer 1. When a region is defined as a side that includes a resonator end surface for projecting signal light for transmission as a front region, and a region on a side that includes a resonator end surface for projecting signal light for monitoring as a back region across the phase shift part, the guide layer 3 may have a difference in composition between portions of the back region and the front region. COPYRIGHT: (C)2008,JPO&INPIT
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