Normal-incidence electroabsorption in Ga1−xAlxSb/AlSb L-valley quantum wells for 3–5 μm optical modulation

Abstract
Theoretical investigations are presented of the electric‐field dependence of normal‐incidence interconduction subband absorption in Ga1−xAlxSb/AlSb L‐valley quantum wells. Under an applied electric field of 50 kV/cm, a blue shift of the absorption peak from 4.94 to 4.82 μm was found in a Ga0.7Al0.3Sb/AlSb structure with well width of 25 Å. The ability to absorb normally incident light and to achieve significant Stark shifts with bias makes the Ga1−xAlxSb/AlSb L‐valley system an attractive choice for the 3–5 μm vertical optical modulators.