| 摘要 |
PROBLEM TO BE SOLVED: To provide an end surface film which has desired reflectivity and can be collectively formed in a two-wavelength semiconductor laser device of a monolithic structure, and provide a two-wavelength semiconductor laser device wherein reliability is high, desired performance is satisfied and productivity is high. SOLUTION: In this two-wavelength semiconductor laser device of monolithic structure, a front end surface 18 of a resonator has a front end surface film 19, and a rear end surface 21 of the resonator has a high reflection end surface film 22 constituted of a multilayer film. In the front end surface film 19, the film thickness is so set that reflectivity becomes 20% by using low refractive index material. In the high reflection end surface film 22, the film thickness is so set that reflectivity becomes 80% by alternately laminating a thin film composed of low refractive index material and a thin film composed of high refractive index material. Film thicknesses of both end surface films are calculated from optical length d=(1/4+j)×λm by usingλm=(λ1+λ2)/2 which shows a mean value of oscillating frequency of both semiconductor laser diodes.
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