Fabrication of photonic wires in LiNbO3 and their interest in nonlinear optics

We used a new Proton Exchange process, the High Index Soft Proton Exchange (HISoPE) process, to realize in a reproducible way, highly confining waveguides without degrading the nonlinear coefficient of the lithium niobate crystals. On a set of waveguides fabricated with different conditions, we measured the crystallographic changes, the index profiles, the local SHG response and the propagation losses, showing the advantages and the issues related to this new waveguides fabrication technique.