Optical element in semiconductor laser device having a diffraction grating and improved resonance characteristics

DETAILED DESCRIPTION Accordingly, an essential object of the present invention is to provide an improved semiconductor laser device in which Fabry-Perot resonance mode is suppressed, while disappearance of a diffraction grating in the manufacturing process is prevented, by employing a technical means in a waveguide structure of a semiconductor laser device having the diffraction grating of a distributed feedback type, distributed Bragg reflection type or the like, with a substantial elimination of disadvantages inherent in the conventional devices of the kind.
Another important object of the present invention is to provide a semiconductor laser device of the above described type which is simple in structure and stable in function with high reliability, and can be readily manufactured on a large scale at low cost.
In accomplishing these and other objects, according to one preferred embodiment of the present invention, there is provided a semiconductor laser device which comprises a first light deriving optical waveguide connected approximately perpendicularly to a light exit face at one side, a second light deriving optical waveguide connected approximately perpendicularly to another light exit face at the other side and having an optical axis different from that of the first light deriving optical waveguide, and a light emitting optical waveguide subjected to optical coupling with a periodical diffraction grating for optical resonance, and connected to end portions of the first and second light deriving optical waveguides within the semiconductor laser device.
By the arrangement according to the present invention as described above, a highly efficient semiconductor laser device has been advantageously presented through a simple structure.