Efficient coupling of light wave into slow modes planar photonic crystal slab waveguides

摘要

The generation of the slow modes in a planar photonic crystal waveguide has been highlighted theoretically and experimentally in the two last decade. However, the exploitation of this phenomenon to control the light propagation in the optical integrated circuits faces several obstacles and technological locks. On the one hand, it is almost impossible to excite this type of modes in the slowing light devices because of the group velocity mismatch and even if we are able to overcome this problem, the frequencies of the slow modes are very close to the band edge which causes the optical signal distortion by high value of group velocity dispersion. On the other hand, the slow modes are characterized by a special spatial distribution of the electromagnetic field which extends beyond the defect which serves as a wave guide, this lead to an intense interaction of a part of the guided light with the holes of photonic crystal and cause the appearance of the different type of losses. Several solutions have been proposed to address these various issues and our contribution is in this perspective, and more specifically, it is trying to find the parameters that enable an optimal coupling of the fast modes of our planar photonic crystal waveguide into his slower one. To achieve this goal, we chose to work in two stages. First, we have sought the structural parameters that will help us to generate a slowly mode with zero-dispersion effect. After, we have worked and demonstrated the efficient static coupling of light into the slow modes photonic crystal waveguide.