| 摘要 |
PROBLEM TO BE SOLVED: To provide a distributed feedback type semiconductor laser capable of achieving high efficiency without impairing stability in an axial mode. SOLUTION: In a refractive index coupled type distribution semiconductor laser having aΛ/2 phase shift type distributed feedback structure, having refractive index coupled diffraction gradings 8, 9 on an active layer 6 when seen in the distribution feedback direction of light, the value of (duty at a high refractive index section 8)/(that at a low refractive index section 9) in the diffraction grating existing in a rear end face side region 1 is made larger compared with a value in the front end face side region 2, thus making larger a coupling factorκ1 in the rear end face side region 1 as compared with a coupling factorκ2 of the front end face side region 2 in a normal semiconductor laser. COPYRIGHT: (C)2009,JPO&INPIT
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