| 摘要 |
PURPOSE:To facilitate the fabrication of a semiconductor laser with no influence on protective effect by selecting the thickness of a protective film on two reflection surfaces of the laser element a value 1/10 or less of the wavelength within the protective film. CONSTITUTION:A protective film 16 of Al2O3 is attached on the sides of a semiconductor laser element having electrodes 6 and 7, and the thickness of the film is set at one tenth or less of the emission wavelength within the film. When the thickness is lambda/2 or is integer times, the reflection factor is the maximum, and its threshold current Ith is almost equal to Ith0 which is for without a protective film. With the rest of thickness, Ith is larger than Ith0. When the film is lambda/10 thick, this is within the order of thickness error, and the distribution of Ith is not different from that for the optimum value lambda/2. When the film is less than lambda/10 thick, the formation time decreases, and the deformation of the reflection surface can be prevented. Therefore, the fraction defective of a luminous characteristic decreases, and also variation of a threshold current due to leaving it under a high temperature decreases. |
