Use of a three-layer quantum-well structure to achieve an absorption edge blueshift

Theoretical calculations are used to propose a novel structure for a quantum-well electro-optic device which gives a large blueshift of the absorption edge on application of an electric field. The structure provides spatial separation of the electron-hole pair in the ground state at zero applied field. This is achieved by use of two materials within the well which have a type II band line-up relative to each other but are type I relative to the barrier material. The combination of InAs0.4P0.6/In0.53Ga0.47As wells with InP barriers is expected to fulfill these requirements and also to operate in the 1.5 μm region.