We have designed and studied a new type of strained semiconductor quantum well structure,variable‐strainquantumwell. The strain within the quantum well is graded from compressive to tensile in order to obtain mutually opposing slopes for the heavy‐ and light‐hole band edges, causing the heavy and light holes to experience opposite fields created by the same strain. A unique bias controlled crossover with a simultaneous red and blue quantum confined Stark shift for the heavy‐ and light‐hole transitions, respectively, has been observed by electroreflectance spectra. This results in a bias controlled change of the polarization properties and the transition energies suitable for polarization controllable photonic devices. ©1995 American Institute of Physics.