Semiconductor laser device, semiconductor laser module, Raman amplifier using the device or module, and method for forming a suitable current blocking layer

摘要

A diffraction grating is provided in the vicinity of a GRIN-SCH-MQW active layer formed between a radiation side reflection coating provided on a radiation end face of a laser beam and a reflection coating provided on a reflection end face of the laser beam, and on the radiation side reflection coating side. An n-InP layer which covers the upper part of the diffraction grating is also provided, so that the current from the p-side electrode is prevented from being injected to the vicinity of the diffraction grating by the n-InP layer. An n-InPGaAsP diffusion prevention layer forms a non-current injection area so as to suppress alloying with the p-side electrode.