www.ijstr.org Multimode Interference Biosensor Working With Multiple Wavelengths And Two Polarizations (original) (raw)

Optimizing the Limit of Detection of Waveguide-Based Interferometric Biosensor Devices

Sensors, 2019

Waveguide-based photonic sensors provide a unique combination of high sensitivity, compact size and label-free, multiplexed operation. Interferometric configurations furthermore enable a simple, fixed-wavelength read-out making them particularly suitable for low-cost diagnostic and monitoring devices. Their limit of detection, i.e., the lowest analyte concentration that can be reliably observed, mainly depends on the sensors response to small refractive index changes, and the noise in the read-out system. While enhancements in the sensors response have been extensively studied, noise optimization has received much less attention. Here we show that order-of-magnitude enhancements in the limit of detection can be achieved through systematic noise reduction, and demonstrate a limit of detection of ∼ 10 - 8 RIU with a silicon nitride sensor operating at telecom wavelengths.

Novel Sensing Algorithm for Linear Read-Out of Bimodal Waveguide Interferometric Biosensors

Journal of Lightwave Technology, 2021

Biosensors employing photonics integrated circuits, and specifically those that rely on interferometric evanescent wave working principles, have outstanding performances due to the extreme sensitivity exhibited in one-step and direct assay, without the need of amplification. Within the interferometric configurations, the Bimodal Waveguide (BiMW) interferometric sensor stands out due to its demonstrated sensitivity for real-life applications and the simplicity of its design. To overcome the ambiguities that arise from the periodic nature of interferometric read-outs, a new all-optical modulation and the subsequent trigonometry-based algorithm have been proposed and applied to the BiMW biosensor. This new algorithm has been successfully employed for the selective identification and quantification of the external Spike (S) protein of the Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2). Our biosensing results from this simple, quick, and user-friendly method demonstrate high sensitivity and specificity and pave the way towards a point-of-care device for general use.

Design and fabrication of slotted multimode interference devices for chemical and biological sensing

Journal of Sensors, 2009

We present optical sensors based on slotted multimode interference waveguides. The sensor can be tuned to highest sensitivity in the refractive index ranges necessary to detect protein-based molecules or other water-soluble chemical or biological materials. The material of choice is low-loss silicon oxynitride (SiON) which is highly stable to the reactivity with biological agents and processing chemicals. Sensors made with

Integrated Bimodal Waveguide Interferometric Biosensor for Label-Free Analysis

Journal of Lightwave Technology, 2000

We report on a field-effect light emitting device based on silicon nanocrystals in SiO 2 deposited by plasma-enhanced chemical vapor deposition. The device shows high power efficiency and long lifetime. We demonstrate that the power efficiency is enhanced up to ~0.1% by the presence of a ~15-nm Si 3 N 4 control layer. The leakage current reduction induced by this buffer effectively increases the power efficiency two orders of magnitude with regards to similarly processed devices with solely oxide . In addition, the Si 3 N 4 cools down the electrons reaching the polysilicon gate contributing to create fewer defects, which significantly reduces the device degradation. a)

Lab-on-a-Chip Integration of the Bimodal Waveguide Nanointerferometric Biosensor

2018

This doctoral Thesis focuses on the integration of the novel Bimodal Waveguide Nanointerferometric Biosensor (BiMW) into a Lab-On-a-Chip (LOC) platform which can allow the direct detection of biomarkers for diseases diagnosis directly in the patient´s sample. Even if real bioanalytical applications have been widely reported by our group xi

Performance of a highly sensitive optical waveguide Mach-Zehnder interferometer immunosensor

Sensors and Actuators B-chemical - SENSOR ACTUATOR B-CHEM, 1993

We describe a highly sensitive sensor which uses the evanescent field of a reusable planar optical waveguide as the sensing element. The waveguide used is optimized to obtain a steep dependence of the propagation velocity on the refractive-index profile near the surface. The adsorption of a layer of proteins thus results in a phase change, which is measured interferometrically using a Mach-Zehnder interferometer set-up. The stability of the interferometer is such that phase changes = (1 × 10-2)2pi per hour can be measured. Immunoreactions have been monitored down to concentrations of 5 × 10-11 M of a 40 kDa protein.

Reducing the temperature sensitivity of SOI waveguide-based biosensors

Silicon Photonics and Photonic Integrated Circuits III, 2012

Label-free photonic biosensors fabricated on silicon-on-insulator (SOI) can provide compact size, high evanescent field strength at the silicon waveguide surface, and volume fabrication potential. However, due to the large thermo optic coefficient of water-based biosamples, the sensors are temperature-sensitive. Consequently, active temperature control is usually used. However, for low cost applications, active temperature control is often not feasible. Here, we use the opposite polarity of the thermo-optic coefficients of silicon and water to demonstrate a photonic slot waveguide with a distribution of power between sample and silicon that aims to give athermal operation in water. Based on simulations, we made three waveguide designs close to the athermal point, and asymmetric integrated Mach-Zehnder interferometers for their characterization. The devices were fabricated on SOI with a 220 nm device layer and 2 µm buried oxide, by electron beam lithography of hydrogen silsesquioxane (HSQ) resist, and etching in a Cl 2 /HBr/O 2 /He plasma. With Cargile 50350 fused silica matching oil as top cladding, the group index of the three guides varies from 1.9 to 2.8 at 1550 nm. The temperature sensitivity of the devices varied from-70 to-160 pm/K under the same conditions. A temperature sensitivity of-2 pm/K is projected with water as top cladding.

SU-8 MICRO-BIOSENSOR BASED ON MACH-ZEHNDER INTERFEROMETER

In this paper design, simulations and preliminary experimental results for an optical biosensor, using a Mach-Zehnder interferometer as basic configuration, are presented. This type of sensor offered a lot of advantages such as compactness, real time analysis, low cost and high sensitivity and the possibility of integration of electronic detection components on the same chip. The integrated optical structure is sensitive to refractive index change induced due to the interaction of the evanescent field with an immobilised biological sample placed on one of the two arms of the interferometer (the sensitive one). A window is open in the upper cladding of the waveguide. Changing the bio specimen produces a variation of the refractive index of the clad-ding layer, which can be observed through the phase shift difference between the light of the two interferometer arms. SU-8 polymer was tested as the core of the optical waveguides, an epoxy-based negative photoresist material, which prese...

Novel chemical sensor/biosensor platform based on optical multimode interference (MMI) couplers

Sensors and Actuators B: Chemical, 2005

We present a novel platform for chemical sensing and biosensing. The working principle is based on the interference properties of an optical multimode interference coupler. A humidity sensor has been implemented as a proof of principle. It has been realised using hybrid sol-gel planar technology to allow integration on a silicon substrate.