| 摘要 |
PROBLEM TO BE SOLVED: To provide a semiconductor laser having narrow spectrum line width, by a method wherein a diffraction grating structure can be improved in a relatively easy manner by changing the structure. SOLUTION: The interface between the second light waveguide layer 14 and the second clad layer 15 consisting of the second region adjacent to the other end part of a resonator and the third region formed between the first and the second regions, and a diffractive lattice 20 is formed in such a manner that it makes a 1/4 wavelength shifting with each other on the first and the second regions. The coupling constant in the third region is smaller than the coupling constant in the first and the second regions, and the waveguide direction of the light in the third region is 1/4 or higher of the resonator length.
|
