Integrated Photonic Platform for Robust Differential Refractive Index Sensor
André L. Moras, C. S. Valnir, Mário C. M. M. Souza, Giuseppe A. Cirino, Antonio A. G. von Zuben, Luís A. M. Barea, Newton C. Frateschi
Abstract
We demonstrate an integrated photonic platform comprising a refractive index (RI) sensor based on Photonic Molecule (PM) that effectively mitigates the influence of environmental perturbations using a differential measurement scheme while providing high quality-factor (Q) resonances. The RI sensor consists of a partially unclad microdisk resonator coupled to an external clad microring resonator fabricated on silicon-on-insulator (SOI) platform. We report a RI sensitivity of 24 nm/RIU, achieving a limit of detection (LOD) of 1.7 × 10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-3</sup> refractive index units (RIU) with improved stability for an operation range of 0.15 RIU in a compact footprint of 40 × 40 μm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> , representing an important solution for real-life applications in which measurement conditions are not easily controllable.