Characterization of a waveguide Mach-Zehnder interferometer using PDMS as a cover layer

摘要: A Mach-Zehnder interferometer made with shallow rib waveguides is studied experimentally and using simulations. The rib-height giving single-mode guidance found as function of core thickness polarization. Devices have been (5 nm height) in silicon nitride. sensitivity the limit detection (LOD) regarding length sensing window for two cover media: water hydrochloric acid (HCl) polydimethylsiloxane (PDMS). For HCl-solution, which standard method testing interferometers, measured LOD was 13000 π rad/RIU 1.1x10^-7 RIU, respectively, a 2 cm long window. This comparable to best results reported previously. With PDMS medium, temperature device increased order measure sensitivity. new approach that makes it possible solid medium has relatively high coefficient refractive index. Measured 15200 1.3x10^-7 again sensitivities agreed simulations linearly expected. However, showed minimum length. mainly due noise 3 length, both HCl-solution PDMS. higher similar compared concluded dependence good alternative interferometers.