Integrated Photonic Platform for Robust Differential Refractive Index Sensor

• Published in: IEEE photonics journal Vol. 12; no. 5; pp. 1 - 10
• Main Authors: Moras, Andre L., Junior, Valnir C. S., Souza, Mario C. M. M., Cirino, Giuseppe A., Von Zuben, Antonio A. G., Barea, Luis A. M., Frateschi, Newton C.
• Format: Journal Article
• Language: English
• Published: Piscataway IEEE 01.10.2020; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Cavity resonators; Integrated optics devices; Microcavities; Microsoft Windows; Optical sensing and sensors; Photonics; Refractive index; Refractivity; Resonators; Sensor; Sensors; Temperature measurement; Temperature sensors
• ISSN: 1943-0655; 1943-0655; 1943-0647
• DOI: 10.1109/JPHOT.2020.3024856

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 −3 refractive index units (RIU) with improved stability for an operation range of 0.15 RIU in a compact footprint of 40 × 40 µm 2 , representing an important solution for real-life applications in which measurement conditions are not easily controllable.