A frequency-selective light coupler-decoupler device comprising a component of photonic crystal structure in which there is formed a waveguide having at least one longitudinal edge with a small number of rows of periodic elements of the photonic crystal so as to form coupling zones between the waveguide and the outside of the photonic crystal at coupling frequencies that are determined in particular by the width of the waveguide and/or by the spatial period of the photonic crystal elements.