Distributed-feedback semiconductor laser

Claim 1

A distributed-feedback (DFB) semiconductor laser diode comprising: an active layer (12) emitting light upon injection of an electric current; an optical waveguide (20), adjoining said active layer (12), for guiding the light together with said active layer (12), said optical waveguide (20) comprising a first semiconductor layer (13) of a first conductivity type adjoining said active layer (12) and having a greater bandgap than that of said active layer, and a second semiconductor layer (14) of the first conductivity type adjoining said first semiconductor layer and having a bandgap smaller than that of said first semiconductor layer (13) but greater than that of said active layer (12), said optical waveguide (20) having a corrugation pattern of a prescribed pitch in the direction of said active layer (12); a first cladding layer (15) of the first conductivity type and a second cladding layer of a second conductivity type, said first and second cladding layers (11) adjoining said optical waveguide (20) and said active layer (12), respectively, and having bandgaps greater than those of said active layer and of said second semiconductor layer; wherein said corrugation pattern is formed on said first semiconductor layer (13), said second semiconductor layer (14) is formed to conform to the corrugation pattern of said first semiconductor layer (13), and the light emitted from said active layer (12) interacts with the diffraction grating formed by the boundary of said corrugation pattern and causes said diode to lase, characterized in that the first and/or the second semiconductor layer(s) (13,14) is/are interrupted at the peaks of the periodic corrugation.