Modal theory of diffraction : a powerful tool for the study of grating couplers in nonlinear opticsR. Reinisch, M. Nevière, H. Akhouayri, J. Danckaert et G. VitrantJ. Phys. III France, 4 12 (1994) 2451-2458DOI: https://doi.org/10.1051/jp3:1994290