The Importance of Single-Mode Behavior in Silicon-On-Insulator Rib Waveguides With Very Large Cross Section for Resonant Sensing Applications

Control of light properties through propagation in large cross section optical rib waveguides is of utmost importance to obtain the desired behavior, especially with resonant cavities. We have simulated, fabricated, and experimentally tested optical rib waveguides to evaluate the advantages of single-mode properties against multimode. Modal analysis of very large cross section rib waveguides showed that only particular dimensions allow a single-mode behavior. Furthermore, on-chip Fabry-Perot cavities were coupled to rib waveguides to assess impacts for a typical resonator. Experimental results are in good agreement with simulation guidelines, effectively highlighting the importance of single-mode behavior for resonant sensing applications.