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摘要

The present invention relates to a semiconductor laser device and a method for fabrication thereof, wherein the semiconductor laser device exhibits an improved mode selectivety. According to the present invention there is provided a semiconductor laser device comprising a first and a second reflecting region (3,5), said first reflecting region being comprising a Bragg mirror (3) with alternating parallel layers having different refractive index, respectively, said first and second reflecting regions being adjacent to a laser active semiconductor region (1) for emitting radiation of a predetermined wavelength and defining a longitudinal laser cavity, exciting means for exiting said laser active semiconductor region causing emission of radiation, wherein said first reflecting region (3) further comprises a contact layer (2) on top thereof, and one additional layer (4) on top of said contact layer (2) covering only a portion of said contact layer, wherein an arrangement of said alternating layers forming said Bragg mirror, an optical thickness of said layer, and a reflectivity and an absorption of said additional layer is selected so as to reduce reflectivity of said reflecting region in said portion of said contact layer covered by said additional layer, resulting in a smaller reflectivity compared to a portion of said contact layer, which is not covered by said additional layer. Moreover, a method is provided in order to fabricate the above mentioned semiconductor laser device, wherein a step of calculation is performed to predict an optimised optical thickness of the contact layer and an optimised composition and thickness of the metallization layer to obtain a desired difference in reflectivity. IMAGE