| 摘要 |
PURPOSE:To make an easy ultrahigh modulation available at low driving current by changing the output optical power from a first semiconductor laser by a method wherein the light is inputted intermittently into N sets of laser amplifiers. CONSTITUTION:When the light is injected into a semiconductor laser amplifier 21 which shares an active layer with a first laser 20, the injected light 4 is amplified by the work of the light amplifier, resulting in reduction of a carrier density within the active layer. Along with this, a carrier density of the active layer 3, which the amplifier shares with the first laser, is also reduced and the output light 5 from the first layer is decreased. When light injection is stopped, the output light power level of the first laser 20 gets back to an original level because a carrier density gets back to an original carrier density distribution. In a modulation using the injected light 4, a light small signal modulation can be obtained as a large modulation output since the work of the light amplifier brings about a large change in carrier density even if the injected light level is small. |
