Modeling and Analysis of SOI Gratings-Based Opto-Fluidic Biosensor for Lab-on-a-Chip Applications

Venkatesha Muniswamy,Prasant Kumar Pattnaik,Narayan Krishnaswamy

doi:10.3390/photonics6020071

Venkatesha Muniswamy, Prasant Kumar Pattnaik + Show 1 more

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https://doi.org/10.3390/photonics6020071

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Abstract

The design, modeling, and analysis of a silicon-on-insulator (SOI) grating coupler integrated with a microfluidic channel for lab-on-a-chip applications are presented. The grating coupler was designed to operate at 1310 nm. The simulated SOI structure consisted of a 220 nm top-Si device layer with an integrated waveguide, grating coupler, and a buried oxide layer of 2 µm. A rectangular microfluidic channel was deposited on the SOI optical grating structure for light and fluid interaction. The fluidic flow through the device was driven by centrifugal and Coriolis forces. The grating structure was designed to achieve a maximum coupling efficiency at the optimized injection angle of the light source. The sensitivity of the grating structure could be analyzed and evaluated using the change in coupled power as a function of the effective refractive index and was found to be 0.928 × 10−6 RIU. The SOI optical grating structure along with the micro fluidic channel on top could be effectively used as an absorbance-based lab-on-a-chip biosensor.

Highlights

Most bio-sensors are developed on silicon-on-insulator (SOI) substrates due to the high refractive index contrast between silicon device layers and buried oxide layers
The simulation and modeling of an SOI grating coupler integrated with a channel operating at 1310 nm was presented
The flow through the device was a result of centrifugal microfluidic channel operating at 1310 nm was presented

Summary

Introduction

Most bio-sensors are developed on silicon-on-insulator (SOI) substrates due to the high refractive index contrast between silicon device layers and buried oxide layers. Silicon is highly transparent in the infrared wavelength region of light, and silicon photonics has emerged as a promising solution for the development of opto-fluidic biosensors operating at the infrared wavelength region of light [1,2]. Recent developments in opto-fluidic-based biosensors have led to many sensors being developed on SOI substrates, which include refractive index sensing and Bragg-grating-based sensors [2,4]. One of the major challenges in optical waveguides is coupling of light between the optical source and the nanoscale waveguide [9,10,11]. One such efficient waveguide coupler that can couple light from the microscale to the nanoscale dimension is the fiber

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