| 摘要 |
<p>PURPOSE:To offer an optical modulator which is driven with a low voltage and has a high quenching ratio and imposes fast modulation by laminating a 2nd semiconductor layer which has a smaller forbidden band with than the forbidden band width of a 1st semiconductor layer which varies in forbidden band width monotonously in the laminating direction on the 1st semiconductor layer. CONSTITUTION:The semiconductor thin film structure of the multilayered structure formed by repeatedly laminating 1st and 2nd semiconductor layers whose film thickness is smaller than the mean free stroke of electrons is sandwiched between a p and an n type semiconductor, and electrodes for applying an electric field in the laminating direction are provided on the top and rear surfaces to constitute the optical modulator. The 1st semiconductor layer varies in the forbidden band width monotonously in the laminating direction and the 2nd semiconductor layer has the narrower forbidden band width than the forbidden band width of the 1st semiconductor layer and the 2nd semiconductor layer is provided in contact with the area where the 1st semiconductor layer has the maximum forbidden band width. Further, the 1st semiconductor layer is increased preferably in the forbidden band width in the laminating direction toward the p semiconductor.</p> |
