| 摘要 |
PROBLEM TO BE SOLVED: To provide a laser device capable of emitting laser beam of a desired wavelength. SOLUTION: A semiconductor laser 201 includes: a first diffracting grating region, in which a plurality of segments composed of a diffraction grating part 2 and a space part are connected, having a gain, and having first discrete peaks of a reflection spectrum; a diffraction grating part having the same pitch as that of the diffraction grating part of the first diffraction grating region; and a second diffraction grating region, in which a plurality of segments composed of a diffraction grating part 2 and a space part are connected, having second discrete peaks of the reflection spectrum different in the interval of the peak wavelength from that of the first discrete peaks of the reflection spectrum; wherein the first segment, being any one of the segments, has an optical length of an odd number times as large as a half of the pitch of the diffraction grating part of the first diffraction grating region, compared to all other segments, and all other segments have optical lengths of an even number times as large as the pitch of the diffraction grating part of the first diffraction grating regions or the optical lengths of an odd number times as large as the half of the pitch of the first diffraction grating region. COPYRIGHT: (C)2007,JPO&INPIT
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