Optimized sensitivity of Silicon-on-Insulator (SOI) strip waveguide resonator sensor

Abstract

Evanescent field sensors have shown promise for biological sensing applications. In particular, Silicon-on-Insulator (SOI)-nano-photonic based resonator sensors have many advantages for lab-on-chip diagnostics, including high sensitivity for molecular detection and compatibility with CMOS foundries for high volume manufacturing. We have investigated the optimum design parameters within the fabrication constraints of Multi-Project Wafer (MPW) foundries that result in the highest sensitivity for a resonator sensor. We have demonstrated the optimum waveguide thickness needed to achieve the maximum bulk sensitivity with SOI-based resonator sensors to be 165 nm using the quasi-TM guided mode. The closest thickness offered by MPW foundry services is 150 nm. Therefore, resonators with 150 nm thick silicon waveguides were fabricated resulting in sensitivities as high as 270 nm/RIU, whereas a similar resonator sensor with a 220 nm thick waveguide demonstrated sensitivities of approximately 200 nm/RIU.

Silicon Photonic Biosensors Using Label-Free Detection

“…An investigation of silicon MRR based biosensor arrays was reported by Xu et al in 2010 with an experimental sensitivity of 135 nm/RIU; binding interactions between complementary IgG protein pairs was monitored with a concentration down to 20 pM by utilizing TM-polarized light [ 124 ]. Fard et al reported a sensitivity enhanced TM mode MRR biosensor by decreasing the thickness of silicon waveguides to 150 nm, resulting in sensitivities as high as 270 nm/RIU and 437.5 pm/nm for bulk and surface analytes [ 19 ]. In 2013, Grist et al introduced Si-based microdisk resonators for label-free biosensing, and experimental results showed sensitivities of 26 nm/RIU and 142 nm/RIU, and Q -factors of 3.3 × 10 4 and 1.6 × 10 4 for the TE and TM modes, respectively [ 21 ].…”

“…Meanwhile, silicon photonics are excellent transducers for continuous and quantitative label-free biosensing [ 14 , 15 ], which can directly respond to affinity interactions between analyte and receptor molecules in real-time. Hence, numerous silicon photonic sensing devices, such as Mach–Zehnder interferometers (MZIs) [ 16 , 17 ], microring resonators (MRRs) [ 18 , 19 ], microdisk resonators [ 20 , 21 ], Bragg grating resonators [ 22 , 23 ], and one-dimensional (1D) or two-dimensional (2D) photonic crystals (PhCs) [ 24 , 25 ] have been developed over the past decades for biosensing diagnostic applications.…”

Progress of infrared guided-wave nanophotonic sensors and devices

“…The closest thickness offered by MPW foundry services of 150 nm was chosen. The bulk sensitivity was measured to be 270 nm/RIU, whereas a similar resonator sensor with a 220 nm thick waveguide demonstrated a bulk sensitivity of approximately 200 nm/RIU [72].…”

TDM-controlled ring resonator arrays for fast, fixed-wavelength optical biosensing

“…Several different concepts for these devices were developed [11]: grating coupled, interferometric, photonic crystal, surface plasmon resonance and ring resonator based sensors were investigated for lab-on-a-chip analytical applications. A comprehensive review can be found in [12,13]. Among these different concepts, ring resonator based biosensors as a chip integrated approach are considered as very capable devices.…”