Semiconductor laser device, semiconductor laser module, and Raman amplifier using the device or module

摘要

A semiconductor laser device which has a diffraction grating partially provided in the vicinity of an active layer formed between a radiation-side reflection film provided on a radiation-side end surface of a laser beam and a reflection film provided on a reflection-side end surface of the laser beam, and which outputs a laser beam having a desired oscillation longitudinal mode based on a wavelength selection characteristic of at least the diffraction grating. The diffraction grating is formed in isolation with an isolation distance of Ls=15 mum from the radiation-side reflection film.