Optical based noninvasive glucose monitoring sensor prototype

Diabetes mellitus claims millions of lives every year. It affects the body in various ways by leading to many serious illnesses and premature mortality. Heart and kidney diseases, which are caused by diabetes, are increasing at an alarming rate. In this paper, we report a study of a noninvasive measurement technique to determine the glucose levels in the human body. Current existing methods to quantify the glucose level in the blood are predominantly invasive that involve taking the blood samples using finger pricking. In this paper, we report a spectroscopy-based noninvasive glucose monitoring system to measure glucose concentration. Near-infrared transmission spectroscopy is used and in vitro experiments are conducted, as well as in vivo. Our experimental study confirms a correlation between the sensor output voltage and glucose concentration levels. We report a low-cost prototype of spectroscopy-based noninvasive glucose monitoring system that demonstrates promising results in vitro and establishes a relationship between the optical signals and the changing levels of blood–glucose concentration

PCF Based Sensor with High Sensitivity, High Birefringence and Low Confinement Losses for Liquid Analyte Sensing Applications

In this paper, we report a design of high sensitivity Photonic Crystal Fiber (PCF) sensor with high birefringence and low confinement losses for liquid analyte sensing applications. The proposed PCF structures are designed with supplementary elliptical air holes in the core region vertically-shaped V-PCF and horizontally-shaped H-PCF. The full vectorial Finite Element Method (FEM) simulations performed to examine the sensitivity, the confinement losses, the effective refractive index and the modal birefringence features of the proposed elliptical air hole PCF structures. We show that the proposed PCF structures exhibit high relative sensitivity, high birefringence and low confinement losses simultaneously for various analytes

SBS-based Tunable Microwave Photonic Notch Filter and Amplifier Simultaneously with Enhanced Gain, Bandwidth, and Polarisation Control up to 50 GHz

Stimulated Brillouin Scattering (SBS) based filters can provide high gain, narrow bandwidth, and wideband tunability, which are critical for modern radio frequency systems. However, it is important to optimise all performance parameters to obtain stable response over wideband along with high gain. We present a novel SBS-based Tuneable Microwave Photonics Notch Filter and Amplifier (TMWPNFA) configuration that can perform notch filtering, selective amplification or both simultaneously by exploiting additional Brillouin gain modes and using both SBS stokes and anti-stokes in single-mode fibre. The TMWPNFA amplification and notch suppression are shown for maximum of 50 GHz in Radio Domain, which is the highest reported tunability to our knowledge. The TMWPNFA exhibits high gain of ≃35dB by employing Radio Frequency Amplifier. The TMWPNFA achieves SBS gains from 24 to 4 dB over the range. The suppression achieved by TMWPNFA ranges from 12 to 3 dB. We demonstrated the SBS pump's RF Mixing approach for increasing the -3dB bandwidth of TMWPNFA to 35 MHz, resulting in greater separation of the amplification and suppression bands. The TMWPNFA phase noise distortion caused by SBS is measured to be < -8.6dBc/Hz at 125 kHz Spacing. The filter achieved sharp -3 dB bandwidth of 20 MHz and Q factor of 200 to 2500. The Degree of Polarisation of the SBS pump is shown to be the source of 6 dB gain control. It is shown that additional sound modes produced by SBS, separated by ≈2 x Bandwidth of SBS can be used for notch filtering while simultaneously achieving selective amplification. The proposed 50GHz TMWPNFA would provide unique benefits for satellite, aerospace and beyond communication technologies

Improved efficiency of microcrystalline silicon thin film solar cells with wide band-gap CdS buffer layer

In this paper, we have reported a new structure based upon an optical simulation of maximum light trapping and management in microcrystalline silicon thin film solar cells by using multi texture schemes and introducing an n-type cadmium sulphide (CdS) buffer layer with the goal of extreme light coupling and absorption in silicon absorber layer. Photon absorption was improved by optimising the front and back texturing of transparent conductive oxide (TCO) layers and variation in buffer layer thickness. We have demonstrated that light trapping can be improved with proposed geometry of 1μm thick crystalline silicon absorber layer below a thin layer of wide band gap material. We have improved the short circuit current densities by 1.35mA/cm2 resulting in a total short circuit current of 25 mA/cm2 and conversion efficiency of 9% with the addition of CdS buffer layer and multi textures, under global AM1.5 conditions. In this study, we have used 2 Dimensional Full Vectorial Finite Element (2DFVFEM) to design and optimize the proposed light propagation in solar cell structure configuration. Our simulation results show that interface morphology of CdS layer thickness and textures with different aspect and ratios have the most prominent influence on solar cell performance in terms of both short circuit current and quantum efficiency

Photonic mixer incorporating all-optical microwave frequency generator based on stimulated brillouin scattering using single laser source

© 2020 The Authors. Published by IEEE. This is an open access article available under a Creative Commons licence. The published version can be accessed at the following link on the publisher’s website: https://doi.org/10.1109/ACCESS.2020.2975667In this paper, we report the theoretical and experimental implementation of a photonic mixer for Radio-Over-Fiber (RoF) transmission systems, which incorporates an all-optical 10.87 GHz microwave frequency signal generator based on beating laser frequency with its first order Stimulated Brillouin Scattering (SBS) frequency shift. A 13GHz Radio Frequency (RF) is down-converted to 2.13 GHz Intermediate Frequency (IF) signal. The proposed system configuration represents a cost-effective photonic mixer that can be deployed for up and down conversion around 11 GHz in RoF transmission systems. The optically generated microwave signal of 10.87 GHz has a phase noise of -109 dBc/Hz at 15-MHz offset. The proposed photonic mixer exhibits a Spurious-Free Dynamic Range (SFDR) of 93dB.Hz 2/3. This RoF transmission system configuration deploys dual parallel Gallium Arsenide (GaAs) Mach Zehnder Modulator as a photonic mixer, and a single laser source as a Brillouin pump and as an optical carrier at the same time. To the best of our knowledge, this type of photonic mixers has not been reported in the literature.This work was supported in part by the Leonardo–Electronics, Defense and Security Systems, Grant RF Broadband Project, under Grant RES-15287.Published versio

Optimisation of dispersion compensating in a long-haul fibre for RF transmission of up to 100Gbit/s by using RZ and NRZ formats

With the recent data rate increase it is very challenging to build a fibre optic network that would enable a high data rate transmission over a long haul distance. The signal suffers large degradation over a certain distance due to distortion by the nonlinear effects of the optical fibres. In particular, transmission of high data rates over existing fibre optic systems, while keeping the cost low, avoiding an increase of the system’s complexity and the usage of expensive devices, would be a very challenging task. In this paper, we address this problem by increasing the transmission distance in the fibre optic links for up to 2500km. We have used Standard Single Mode Fibre (SSMF) and Dispersion Compensation Fibre (DCF), where DCF is used as a loss compensator in Radio-Over-Fibre (RoF) systems. A mixture combination of the pre, post and symmetrical fibre compensation schemes were developed to overcome the dispersion in the fibre. We have found that in order to achieve high RF over fibre optic system performance for high data rates and long transmission, there is a requirement to upgrade the optical configuration scheme in a proportional way, by raising the length of the fibre span, compensation span and amplification. We have reported optimised RF over fibre configuration schemes that would have a great impact on reducing the cost, reducing the system’s complexity and avoiding usage of expensive devices, in order to achieve high data rate transmission over existing fibre optic systems

Novel Method for Improving the Capacity of Optical MIMO System Using MGDM

In current local area networks, multimode fibers (MMFs), primarily graded index (GI) MMFs, are the main types of fibers employed for data communications. Due to their enormous bandwidth, it is considered that they are the main channel medium that can offer broadband multiservices using optical multiplexing techniques. Amongst these, mode group diversity multiplexing (MGDM) has been proposed as a way to integrate various services over an MMF network by exciting different groups of modes that can be used as independent and parallel communication channels. In this paper, we study optical multiple-input–multiple-output (O-MIMO) systems using MGDM techniques while also optimizing the launching conditions of light at the fiber inputs and the spot size, radial offset, angular offset, wavelength, and the radii of the segment areas of the detectors. We propose a new approach based on the optimization of launching and detection conditions in order to increase the capacity of an O-MIMO link using the MGDM technique. We propose a (3 $times$ 3) O-MIMO system, where our simulation results show significant improvement in GI MMFs' capacity compared with existing O-MIMO systems. Optical multiple-input-multiple-output multiplexing of parallel communication multichannels over a single multimode fiber network. Optical multiple-input-multiple-output multiplexing of parallel communication multichannels over a single multimode fiber network

A Linearized Analog Microwave Photonic link with an Eliminated Even-order Distortions

International audienceAn improved linearized analog microwave photonic link (AMPL) with significant multioctave bandwidth performance is experimentally presented. The proposed AMPL configuration is based on a double dual-parallel Mach-Zehnder modulator and a differential balanced photodetector (BPD). Explicitly, a gallium arsenide (GaAs)-based modulators are used as opposed to the commonly known lithium niobate (LiNbO3) modulators, due to its robustness in the harsh environment. The system configuration is designed to process a carrier suppressed double-sideband signal through the link, and then at the receiver, a carrier suppressed double-sideband signal is combined with an unmodulated optical carrier, which is transmitted through a polarization maintained (PM) optical fiber. In our experiment, only PM-based optical components are used for better system stability. The developed theoretical model of the proposed system illustrates the elimination of even-order distortions and a high suppression to the third-order intermodulation distortions at the BPD. Consequently, the fundamental signal to interference ratio of 60 dB was experimentally achieved. Furthermore, experimental results, simultaneously, demonstrate a significant increase of second-order spurious-free dynamic range and third-order spurious-free dynamic range by 19.5 and 3.1dB, respectively, compared to the previously reported AMPL performances based on polarization multiplexing dual-parallel Mach-Zehnder modulator. To the best of our knowledge, this is the highest dynamic range AMPL system performance deploying GaAs electro-optic modulator which has most significant capabilities in managing RF signals and exhibits excessive performance in harsh operating environment in terms of thermal stability, power-handling, radiation resistance and longevity for aerospace, defense, and satellite-to-ground downlink communication system applications