A waveguide structure includes a supporting substrate and a waveguide having at least one guide layer with a refractive index n1. This layer comprises a zone of birefringence B which comprises voids provided in the thickness of the guide layer filled with a fluid or material having a refractive index n2. These are organized in at least two parallel rows, each row being in a plane perpendicular to the surface of the guide layer and parallel to the direction of propagation of the optical wave in the guide layer; each row extending over a distance equal to or greater than the wavelength of the optical wave; the width of the voids being ≦ 1/10th of the wavelength of the optical wave; each void within one row being at a distance from an adjacent void of ≦ 1/10th of the wavelength of the optical wave.