| 摘要 |
PURPOSE:To simplify the configuration of a device to make it small and to expand changed wavelength regions by controlling directly the oscillation of a semiconductor laser with an input light signal. CONSTITUTION:On a portion of an active layer 11 of a semiconductor laser is formed an absorption layer 10 which is a saturable region formed of a semiconductor medium having a band gap energy lower than that of the active layer medium. Current injection electrodes 7, 7', separated into active and absorption regions, are provided, and signal light is made to enter an upper absorption layer 10 from a direction normal to oscillating light. Then, when currents Io, Ia are injected forwardly to the separated current injection electrodes 7, 7' respectively, light output-current characteristics show a hysteresis characteristics, and the absorption layer 10 acts as a saturable absorption layer, thereby realizing bistable characteristics. Therefore, when the peak power of incident light is above a prescribed value, an input light pulse signal of a certain wavelength is changed into an output light pulse signal of a waveform determined by the composition of an active layer 11. As a result of this, a conversion system, simple in construction, can be manufactured monolithically, and a conversion system having a wide wavelength region can be constructed. |
