Characterization of a photonic strain sensor in silicon-on-insulator technology

Recently there has been growing interest in sensing by means of opticalmicroring resonators in photonic integrated circuits that are fabricated insilicon-on-insulator (SOI) technology. Taillaert et al. [Proc. SPIE 6619, 661914(2007)] proposed the use of a silicon-waveguide-based ring resonator as a straingauge. However, the strong lateral confinement of the light in SOI waveguides andits corresponding modal dispersion where not taken into account. We present atheoretical understanding, as well as experimental results, of strain applied onwaveguide-based microresonators, and find that the following effects play importantroles: elongation of the racetrack length, modal dispersion of the waveguide, andthe strain-induced change in effective refractive index.