The inherent optical anisotropy of a strained [110]‐oriented multiple quantum well structure is used to make an optically addressed light modulator based on polarization rotation. The anisotropy of the multiple quantum well absorption coefficient for orthogonal polarizations causes rotation of the plane of polarization of light passing through the structure. By partially bleaching the quantum well exciton, the amount of polarization rotation is changed, and therefore modulation of the amplitude of the transmitted beam is achieved. ©1995 American Institute of Physics.