| 摘要 |
<p>PROBLEM TO BE SOLVED: To obtain a semiconductor laser device which is suitable for a light source for a Raman amplifier, capable of obtaining stable and high gain. SOLUTION: The semiconductor laser device comprises a diffraction grating 13a, at least at a reflecting film 14 side near an active layer 3 formed between an emission-side reflection film 15, having a reflectivity of 5% or less and is provided on the emission end face of a laser beam and the film 14, having reflectivity of 80% or more and provided on the reflecting end face. The grating 13a has a value equal to the coupling coefficient of the grating multiplied by a length Lgr of the grating of 2 or more, and emits a laser beam, having two or more oscillating longitudinal modes within a half value of the oscillation wavelength spectrum, by combinedly setting an oscillation parameter, which includes a resonator length LR formed by the layer 3 and the wavelength selection characteristics of the grating Lgr.</p> |
