| 摘要 |
PURPOSE:To offer the optical waveguide which can obtain large variation in refractive index with small heat generation as to an optical waveguide which uses the quantum well layer of a mixed crystal semiconductor and the control method for the light signal which uses the optical waveguide. CONSTITUTION:In the quantum well structure including a single crystal substrate of a 1st material having a 1st grating constant and plural quantum well layers 1 which are formed on the single crystal substrate and sandwiched between barrier layers, the quantum well layers are formed of a 2nd material which is a mixed crystal semiconductor; and the composition of the 2nd material almost match the composition having the narrowest gap in a composition area whose grating matches the single crystal substrate of the 1st material, and the thickness of the quantum well layers 1 is so selected that the energy between base potentials of charge carriers in the quantum well layers 1 is >=50meV higher than specific photon energy, thus constituting the quantum well structure 3. Then the optical waveguide has this quantum well structure 3, a p-type semiconductor area 4 arranged in contact with the quantum well structure 3, an n-type semiconductor area 5, and a (p) side electrode and an (n) side electrode which are connected to the p-type semiconductor area 4 and n-type semiconductor area 5. |
