The design, optical characterization and sensoristic capability provided by a complementary metal-oxide-semiconductor (CMOS) compatible integrated sensor based on a μ-disk resonator cavity are reported. The working principle of the presented device consists in monitoring the changes in the effective refractive index of the supported optical modes induced by variations of the refractive index of the surrounding material. The detection system has been designed on the base of a high quality factor (Q=1.4×10⁴) Si-rich Si₃N₄ (SRSN) μ-disk - emitting in the VIS under optical pumping - bottom coupled to a low loss passive stoichiometric Si₃N₄ waveguide (WG), with losses values under 1 dB/cm measured in the same spectral region. The PL emission in the VIS range provided by the SRSN enable the use of Si-based detectors, easily integrable using the current CMOS standard technology. Proof of concept measurements performed on the coupled device revealed a good sensitivity of 51.79 nm/RIU (Refractive Index Unit), in accordance with the simulated data, and a minimum detection limit of 1.1 × 10^-3 RIU.

Date Published: 9 May 2012
PDF: 8 pages
Proc. SPIE 8431, Silicon Photonics and Photonic Integrated Circuits III, 84311B (9 May 2012); doi: 10.1117/12.921881

Published in SPIE Proceedings Vol. 8431:
Silicon Photonics and Photonic Integrated Circuits III
Laurent Vivien; Seppo K. Honkanen; Lorenzo Pavesi; Stefano Pelli, Editor(s)