摘要:
In the semiconductor laser device of the present invention, a semiconductor stacked structure including an active layer comprising a strained multi-quantum well structure is formed on a substrate 1, a cavity length is larger than 1000 µm but equal to or smaller than 1800 µm, and a low-reflection film S 1 having a reflectance of 3% or less is formed on one facet and a high-reflection film S 2 having a reflectance of 90% or more is formed on the other facet. The semiconductor laser module has a structure in which the semiconductor laser device is set to a cooling device constituted by electrically alternately arranging 40 pairs or more of the Peltier elements and holding them by top and bottom ceramic plates and sealed in the package. A grating having a reflection bandwidth of 1.5 nm or less is formed on an optical fiber to be built in.