| 摘要 |
PROBLEM TO BE SOLVED: To increase the end face optical damage photooutput for lowering the threshold value, by a method wherein oscillation photosignal is emitted at an wavelength not exceeding a specific level while a reflection part positionally and partially reflecting the photosignal is provided at least near one end face. SOLUTION: The wavelength of oscillation photosignal of a semiconductor laser is specified not to exceed 1.1μm. Besides, an active layer 604 made of either GaInP base or AlGaInp base III-IV group semiconductor is provided while a distribution feedback(DFB) structure made of periodical irregularities in a resonator direction for making the periodical fluctuation in refractive index in the resonator direction is erected at least near one end face of a laser resonator. In such a constitution, when a DFP reflecting film 609 is applied, the sum of a forward traveling wave near end face and the photointensity of reflecting wave is equalized with the photointensity taken out of the resonator. Accordingly, the end face optical damage (COD) photooutput is made always constant regardless of the reflecting power, thereby enabling the COD photooutput to be increased.
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