| 摘要 |
PROBLEM TO BE SOLVED: To obtain a nitride based semiconductor laser which can be used as the light source of optical disc over a wide temperature range by forming a dielectric film causing variation in the gain of laser medium depending on the laser wavelength on the front and rear end faces of the resonator of a nitride based semiconductor laser chip composed of a nitride compound of group V element. SOLUTION: Dielectric films 4, 5 for causing variation in the gain of a laser medium depending on the laser wavelength are formed on the front and rear end faces 2, 3 of the resonator of a nitride based semiconductor laser chip composed of a nitride compound of group V element, e.g. Al, Ga or In. Thickness of these dielectric films 4, 5 is set at an optical length (a value determined by dividing the wavelength of laser light in vacuum by the refractive index of the dielectric films 4, 5) which is equal to integer times of one half of the wavelength of laser light. The semiconductor laser thus obtained can be used as the light source of optical disc over a wide temperature range.
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