| 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 linear groove provided in a light absorbing region is further provided in continuity across a light absorbing layer 14 and a third clad layer 15. The part of the groove which is filled with a fourth clad layer 17 presents a higher refractive index and forms a guiding mechanism of positive refractive index. A high reflection film 28 is formed on the end face adjacent to the groove, whereby non-saturation absorption is increased to accelerate bistable operation. When a ratio of a length of a region of the active layer covered with the light absorbing layer to a length of the active region in the length of a resonator is h:(1-h), and a loss alpha of light received by the region of the active layer covered with the light absorbing layer is standardized loss beta=halpha/tau when tau is cavity loss, a ratio ga/gb of a differential gain factor in the active region to that in the region of the active layer covered with the light absorbing 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). |
