Distributed feed back laser with a grating structure adjusted for a reduced intermodulation distortion in an analog amplitude modulation and method for fabricating the same

摘要

The present invention provides a grating structure partially provided in a semiconductor laser device having a first facet of a first reflectivity and a second facet of a second reflectivity which is larger than the first reflectivity. The grating structure extends within a half area near the first facet in the semiconductor laser device. The grating structure has a grating length in a cavity direction of not more than one third of a cavity length defined as a distance between the first and second facets. The grating structure has an integrated coupling coefficient value in the range of 0.4-0.6, the integrated coupling coefficient value is obtained by integrating coupling coefficient of the grating structure with positions in the cavity direction.