Complex-coupled distributed feedback semiconductor laser device

摘要

A complex-coupled DFB laser device (10) including a resonant cavity, and a diffraction grating (20) and an active layer (16) disposed in the resonant cavity, the diffraction grating (20) including alternately a grating layer (20c) having an absorption layer (20a) for absorbing laser having an emission wavelength of the resonant cavity, and a buried layer (22) filled in a space around the grating layer (20c) and formed by a material having an equivalent refractive index higher than that of the grating layer (20c) and a bandgap wavelength smaller than that of the active layer (16). The DFB laser can be realized lasing in the single mode at the longer wavelength side than the Bragg's wavelength, and scarcely generates the multi-mode lasing and the mode hopping irrespective of a higher injection current. <IMAGE>