A SiON Microring Resonator-Based Platform for Biosensing at 850 nm

Abstract

In this paper we report on the design, fabrication and characterization of a photonic circuit for biosensing applications. Silicon oxynitride with a bulk refractive index of 1.66 is the core-layer material. The photonic circuit is optimized for a wavelength of ~850 nm, which allows on-chip integration of the light source via cost effective vertical-cavity surface-emitting lasers and of the detector by using standard silicon photodetectors. Design as well as fabrication processes are explained in details. The best characteristics for the single optical components in the photonic circuit are: for single-mode channel waveguides with dimensions of 350 nm × 950 nm; propagation losses of 0.8 dB/cm; bending losses of 0.1 dB/90 0 -bend (radius of curvature 100 µm); 49/51 splitting ratio for 3-dB power splitters (directional couplers); quality factors up to 1.3×10 5 for microring resonators. Volumetric sensing yields a bulk sensitivity of 80 nm/RIU and a limit of detection of 3×10 -6 RIU. Therefore, SiONbased photonic circuits represent a reliable material platform for biosensing in the short-wave near infrared region.

Al2O3microring resonators for the detection of a cancer biomarker in undiluted urine

“…The LOD is limited by the noise of the system due to temperature fluctuations and laser wavelength or intensity variations [18]. Label-free detection of biomarkers using MRRs has been demonstrated in different integrated photonic platforms, including silicon-on-insulator (SOI) [19][20][21], silicon oxynitride [22] and silicon nitride [23]. However, biological samples, such as blood, urine or saliva, are complex matrices that must be properly processed to remove interfering substances (proteins, metabolites).…”

Portable microresonator-based label-free detector: monotonous resonance splitting with particle adsorption

“…In order to bring this emerging technology closer to the ultimate goal of a low-cost, point-of-care diagnostic instrument, these microresonators have been integrated in photonic platforms, such as silicon-on-insulator [21][22][23], silicon nitride [24][25][26], silicon oxynitride [27] and aluminium oxide [28]. In these settings, multiplexed arrays have been demonstrated, where each ring microresonator is chemically functionalized for a specific response to a distinct type of molecule [29][30][31] and the array has been coupled to microfluidic channels [24].…”

Al<inf>2</inf>O<inf>3</inf> Microresonator Based Passive and Active Biosensors

“…Their operation is based on monitoring the change of resonance wavelength induced by a dielectric perturbation. Some of the best sensor performances regarding sensitivity, limit of detection and clinically relevant biomarker detection have been demonstrated on SOI [1], Si 3 N 4 [2] and SiON [3] technologies.…”