Electroabsorption enhancement in tensile strained quantum wells via absorption edge merging

Electroabsorption in quantum wells under biaxial tension is investigated theoretically. It is found that enhanced electroabsorption due to a field-induced merging of the light and heavy hole absorption edges can be achieved in these structures at moderate operating fields. Calculations showing this merging and electroabsorption enhancement for In_xGa_1-xAs-InP and GaAs_xP_1-x-Al_0.35Ga_0.65As quantum well structures are described. Trade-offs involving the advantages of merged absorption edges are identified through comparisons of tensile strained modulators utilizing the merging effect of analogous lattice matched structures. Optimal structures for operation at 1.55 μm in In_xGa_1-xAs-InP and 0.77 μm in GaAs_xP_1-x-Al_0.35Ga_0.65As are identified, and the sensitivities of their electroabsorption characteristics to material and structural parameters are examined