| 摘要 |
PURPOSE:To reduce a difference between a refractive indexes and to suppress crosstalk to a low level by comparatively independently controlling a band gap in accordance with the well of a multiplex quantum well (MQW) and the component and thickness of a barrier and an average refractive index based on the ratio of the well and the component and thickness of the barrier. CONSTITUTION:When control light 10 is not made incident upon an optical waveguide 11, signal light 12 made incident upon an optical waveguide 13a is straight advanced as it is and emitted. When the control light having 0.85mum wavelength lambdaex equal to the exciton peak wavelength of the MQW is made incident upon the waveguide 11, the control light 10 is arrived from the waveguide 11 to an MQW reflecting part 6. The control light 10 is absorbed into the MQW at the part 6, the exciton peak of the MQW disappears and a refractive index is reduced at wavelength lambda1(>lambdaex), so that the signal light 12 is totally reflected by the reflection part 6 and outputted from an optical waveguide 13b. At that time, the refractive index is sharply changed by the control light 10 only in the reflection part 6 and an interface generating the change of the refractive index is extremely sharpened. Consequently, crosstalk at the time of total reflection can be extremely reduced. |
