Optimal Design of Silicon Photonic Wire Biosensors for High Sensitive Detection

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www.seipub.org/aber

Advances in Biomedical Engineering Research (ABER) Volume 2, 2014

Optimal Design of Silicon Photonic Wire Biosensors for High Sensitive Detection Yaping Zhang, Qinyang Sun The University of Nottingham Ningbo China, 199 Taikang East Road, Ningbo, 315100, China yaping.zhang@nottingham.edu.cn Abstract Silicon photonic wire biosensors’ homogenous detection sensitivities with TE and TM modes for typical test solutions have been investigated. The highest homogenous detection sensitivity of 0.8486 has been achieved when the silicon photonic wire’s width and core thickness are of 0.5μm and 0.22μm for TM mode homogenous sensing. It was found that the homogenous detection sensitivity of TM mode of a silicon photonic wire is about 7 times of that of a TE mode. Silicon photonic wires’ homogenous detection sensitivities are also compared with that of a Silicon on Silica (SOI) rib waveguide, and it was found that the homogenous detection sensitivity of a silicon photonic wire is generally a few thousand times of that of a SOI rib waveguide for either TE or TM mode. Keywords Biosensors; Lab on a Chip; Silicon Photonic Wire Detection; Evanescent Field Detection; Detection Sensitivity

Introduction Many research results have shown that silicon photonic wire evanescent field biosensors have the highest sensitivity of detection compared with other waveguide platforms. It is well-known that SOI material and its fabrication technology have been well established for telecommunication applications, which may find wide applications in biosensing. Recently, great efforts have been put into the exploitation of these advanced technologies for their implementations in biosensing application areas, especially for multiple detection and parallel processing of multiple analytes in multiple test solutions simultaneously and instantaneously in real time. This study has investigated the homogeneous detection sensitivities of silicon photonic wire waveguide ‘lab on a chip’ biosensors with varied silicon photonic wires’ core thickness and ridge width, for the purpose of homogenous sensing applications with TE and TM modes. This has been carried out for typical test solutions with refractive index in the ranges of 1.3∼1.35 and 1.4∼1.485. The homogenous detection sensitivity of a silicon photonic wire has also been compared with that of a SOI rib waveguide. Optimal Design of Highly Sensitive Silicon Photonic Wire Biosensors The side view of a silicon photonic wire biosensor is shown in Fig. 1. It shows that the guided light extends its tail into a text solution in the form of evanescent field. The sensing surface has been functionalized with antibody which can be combined with the analytes in the test solution and hence sense its concentration.

FIG. 1 SIDE VIEW OF A SILICON PHOTONIC WIRE BIOSENSOR

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