| 摘要 |
PURPOSE:To improve controllability and reproducibility by forming multilayer structure of a semiconductor having a band gap larger than an active layer and making specific conditions to hold among the gain coefficients of first and second active regions having positive index differences to the active layer and the natural life of carriers. CONSTITUTION:Multilayer structure in which an active layer is held by a semiconductor having a band gap larger than the active layer is shaped, mutually parallel striped first and second active regions, which have a band gap smaller than the band gap of the active layer while having positive effective index differences to the active layer, are formed in the longitudinal direction of a resonator into the active layer, the first and second active regions are not brought into contact with both reflecting surfaces of the resonator, and the following relationship by formula is established among gain coefficients in the active regions and the natural life of carriers in the active regions. Accordingly, the astigmatism of outgoing beams from both resonators can be made the same, both outgoing beams are focussed by the same lens, and both active regions are separated from sections in the vicinity of the reflecting surfaces, thus displaying an effect for protecting the reflecting surfaces, then improving the reliability of a laser element, provided that reproducibility and yield are enhanced. |
