| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a broad area type semiconductor laser that achieves wavelength control using DFB at a practical level. Ž<P>SOLUTION: Two diffraction gratings 23A and 23B are formed on the interface between a substrate 10 and an n-type cladding layer 11. The diffraction gratings 23A and 23B are formed at such both ends of a band-like optical waveguide region 24 (not shown) corresponding to a ridge 19 as in the band-like region extending along the extending direction of the ridge 19. A wavefront becomes flat at both ends of the optical waveguide region 24 due to index guide, so that oscillation occurs at a predetermined wavelength due to feedback by the diffraction gratings 23A and 23B at both ends of the optical waveguide region 24, thereby inducing oscillation at the center of the optical waveguide region 24 after the oscillation at both ends of the optical waveguide region 24. Ž<P>COPYRIGHT: (C)2010,JPO&INPIT Ž
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