DISTRIBUTION FEEDBACK TYPE SEMICONDUCTOR LASER ELEMENT

摘要

PURPOSE:To reduce the laser oscillated threshold value simultaneously improving the externally differentiated quantum efficiency by a method wherein gratings made of a material with refractive index different from that of a compound semiconductor layer is formed in the compound semiconductor layer. CONSTITUTION:A clad layer 25, an active layer 24 and a guidewave channel layer 23 are successively crystal-grown on a substrate 26 and then gratings 28a, 28b of SiO2 are formed by means of patterning process using two flux interference or electronic beam exposure. Next another clad layer 22 and a contact layer 21 are successively crystalized by means of liquid epitaxial process. Then an electrode 20 and another electrode 27 are respectively formed of Au/Zn and Au/Sn alloy. The optical resonance may occur between the gratings 28a and 28b increasing the feedback efficiency remarkably up to 20 times compared with the conventional efficiency. Resultantly the laser threshold value may be reduced improving the externally differentiated quantum efficiency remarkably.