SEMICONDUCTOR LASER DEVICE

PURPOSE:To enable to reliably obtain an APC signal even if the reflectivity of the lower end of a semiconductor laser element is set to 1 or near this value by applying part of a laser light emitted from the upper end of the element as a monitoring light to a photoelectric converter mounted on the ceiling of a conductive sealing vessel. CONSTITUTION:A photodiode 7 of a photoelectric converter is bonded to the ceiling surface of a metal vessel 11, and the top of an external lead is connected through a soft metal 13 such as an indium to the opposite surface side to the bonded surface. With this structure, a photodiode 7 receives part of a laser light emitted from the upper end of a semiconductor laser element 6 as a monitoring light, photoelectrically converts it and outputs as an APC signal. Accordingly, it is not necessary to emit the laser light from the lower end for monitoring. Since the vessel 11 is electrically connected to a metal stem substrate 4 by sealing, an electrically equivalent state to the conventional structure for bonding the photodiode 7 directly to the metal stem substrate 4 can be obtained.