| 摘要 |
PURPOSE:To provide a stably operating bistable semiconductor laser capable of performing bistable operation in a larger current region and having improved reproducibility, based on a principle of bistable operation, by forming a light absorbing region instead of providing an absorbing region by difference in carrier injection. CONSTITUTION:A bistable semiconductor laser of the invention has a first blocking layer 14 formed along the length of a resonator of a linear active region 21 and adjacent to a second clad layer 13. The first blocking layer 14 serves as a light absorbing layer to light generated by the laser. The linear active region 21 has a band gap smaller than that of the active layer outside thereof. Accordingly, even if the linear active region 21 is placed apart from the reflecting surface, it can transmit laser light without absorbing it. When a ratio of a length of a non-excited region of the active layer under the light absorbing layer region to a length of the active region is h:(1-h) and a loss alpha of light received by the non-excited region of the active layer is a standardized loss beta=halpha/tau when tau is cavity loss, a ratio ga/gb of a diffferential gain factor of the active region to that of the non-excited region of the active layer and a ratio taua/taub of natural carrier lives of these regions have a relation represented by ga.taua/gb.taub<(-beta)/(1-beta). |
