| 摘要 |
PROBLEM TO BE SOLVED: To provide a semiconductor laser device such as a ridge type InGaAlAs system DFB laser element which can form a high reflection film structure having a multitude of films (a plurality of layers of dielectric multilayer films) without causing film peeling.SOLUTION: A DFB laser device 22 has a structure including a DFB laser 30 including an HR film 18A consisting of dielectric multilayer films of a structure having an AR film 14 on a front end surface, and pairs of, for example, three pairs of a low-refractivity film 18a and a high-refractivity film 18b on a back end surface; an InP block 19 which is a transparent block including an HR film 18B consisting of dielectric multilayer films of a structure having pairs of, for example, two pairs of a low-refractivity film 18a and a high-refractivity film 18b on one end surface; and an HR film structure 18 formed by contacting the HR film 18B in the InP block 19 with the HR film 18A in the DFB laser 30. It further includes a low-refractivity adjustment film 18c between the HR film 18B and the InP block 19. |
