APPROACH TO DETERMINING THE VALUE OF THE DYNAMIC RANGE OF AN OPTICAL RECEIVER THAT IMPLEMENTS DIRECT AND HETERODYNE DETECTION METHODS

2020 ◽  
pp. 86-91
Author(s):  
А.Ю. Козирацкий ◽  
А.И. Гревцев ◽  
Р.И. Буров
Keyword(s):  
Dynamic Range ◽  
Direct Detection ◽  
Decisive Role ◽  
Comparative Assessment ◽  
Optical Receiver ◽  
Heterodyne Detection ◽  
Detection Methods ◽  
Detection Scheme ◽  
Value Analysis ◽  
Detection Schemes

Рассматриваются вопросы, связанные с определением возможностей использования фотодетекторов в различных схемах детектирования при приеме сигналов с изменяющейся амплитудой. Определены особенности влияния реализуемых на практике схем детектирования на величину динамического диапазона фотодетектора и потенциально достижимую чувствительность. Разработан подход, позволяющий провести сравнительную оценку изменения величины динамического диапазона в зависимости от реализуемой схемы оптического приемника. Показано, что в отличие от схемы прямого детектирования, где величина динамического диапазона напрямую определяется свойствами самого фотодетектора, при гетеродинном детектировании основную роль в определении указанной величины играет уровень опорного колебания. Анализ полученных результатов показывает, что адаптивное управление величиной опорного колебания при переходе к схеме гетеродинного детектирования с сохранением типа фотодетектора позволяет не только существенно расширить диапазон изменения амплитуды принимаемых сигналов и максимизировать величину динамического диапазона, но и реализовать потенциально достижимую чувствительность, величина которой определяется шумовыми свойствами самого фотодетектора. Конкретизация типа рассматриваемых фотодетекторов позволила ограничиться рассмотрением только теплового и дробового шумов. Определение величины динамического диапазона для других типов фотодетекторов в рамках данного подхода возможно с учетом присущих им шумовых свойств Here we consider issues related to determining the possibilities of using photodetectors in various detection schemes when receiving signals with varying amplitudes. We determined the features of the influence of practical detection schemes on the value of the dynamic range of the photodetector and the potentially achievable sensitivity. We developed an approach that allows for a comparative assessment of changes in the dynamic range depending on the implemented optical receiver scheme. We show that in contrast to the direct detection scheme, where the value of the dynamic range is directly determined by the properties of the photodetector itself, in the case of heterodyne detection, the level of the reference oscillation plays a decisive role in determining this value. Analysis of the obtained results shows that adaptive control of the reference oscillation value when switching to the heterodyne detection scheme with the preservation of the photodetector type allows us not only to significantly expand the range of changes in the amplitude of the received signals and maximize the dynamic range but also to realize a potentially achievable sensitivity, the value of which is determined by the noise properties of the photodetector itself

Laser Far-Field Spot Test System

2013 ◽  
Vol 823 ◽  
pp. 331-334
Author(s):  
Yi Fei Ma
Keyword(s):  
Laser Beam ◽  
Direct Detection ◽  
Beam Quality ◽  
Block Diagram ◽  
Single Pulse ◽  
Test System ◽  
Indirect Detection ◽  
Detection Methods ◽  
Single Chip ◽  
Detection Scheme

Measurement of the energy distribution of laser spots is an effective way in characterizing and diagnosing laser beam quality. After comparing conventional direct-detection and indirect-detection methods, a novel direct-detection scheme, which is based on detector-array controlled by single-chip microprocessors, is proposed. On the basis of analyzing key technologies such as data transmission and optical-electrical conversion, a block diagram of the system is proposed. In this system, a distributed structure was adopted which was composed of a host PC, a main microprocessor and lower microprocessors. This system is capable of measuring the parameters of laser beam in outfield such as size and shape of the spot, the energy of pulse and its distribution etc. It is suitable for most of lasers with repetition rate ranging from single pulse to several hundred per second and different energy up to moderate-high level. The system is more accurate than any former systems.

scholarly journals Simulative Investigation of FMCW Based Optical Photonic Radar And Its Different Configurations

2021 ◽  
Author(s):  
Abhishek Sharma ◽  
Jyoteesh Malhotra
Keyword(s):  
Thermal Noise ◽  
Continuous Wave ◽  
Direct Detection ◽  
Smart Cities ◽  
Autonomous Vehicle ◽  
Coherent Detection ◽  
Target Range ◽  
Detection Scheme ◽  
The Cost ◽  
Detection Schemes

Abstract Intelligent transportation is becoming integral part of future smart cities where driverless operations may provide hassle free conveyance. Photonic radar technology is one such contender to deliver attractive applications in autonomous vehicle sector. In this paper we have discussed the basic principle of frequency modulated continuous wave (FMCW) photonic radar and their possible advantages. Further the basic detection schemes that is direct detection and coherent detection is explained mathematically as well as numerical simulations to understand workings is also carried out. The obtained results concludes that direct detection scheme provides minimal complexity in its architecture and is sensitive to received signal strength at the cost of thermal noise and poor sensitivity. On the other hand, coherent detection offers higher target range estimation as well as velocity measurement at the expense of increased system complexity.

Analysis on Upper Limit of Dynamic Range of Fiber Optic Interferometric Hydrophone Using Digital Heterodyne Detection Scheme

2011 ◽  
Vol 31 (8) ◽  
pp. 0806011 ◽  
Author(s):  
张楠 Zhang Nan ◽  
孟洲 Meng Zhou ◽  
饶伟 Rao Wei ◽  
熊水东 Xiong Shuidong
Keyword(s):  
Fiber Optic ◽  
Dynamic Range ◽  
Heterodyne Detection ◽  
Detection Scheme ◽  
Upper Limit

scholarly journals Label-Free Sensing in Microdroplet-Based Microfluidic Systems

Chemosensors ◽  
2018 ◽  
Vol 6 (2) ◽  
pp. 23 ◽  
Author(s):  
Ali Kalantarifard ◽  
Abtin Saateh ◽  
Caglar Elbuken
Keyword(s):  
Sample Volume ◽  
Detection Methods ◽  
Label Free ◽  
Microfluidic Systems ◽  
Microfluidic Platforms ◽  
Detection Scheme ◽  
Detection Techniques ◽  
Detection Schemes ◽  
Targeted Approach

Droplet microfluidic systems have evolved as fluidic platforms that use much less sample volume and provide high throughput for biochemical analysis compared to conventional microfluidic devices. The variety of droplet fluidic applications triggered several detection techniques to be applied for analysis of droplets. In this review, we focus on label-free droplet detection techniques that were adapted to various droplet microfluidic platforms. We provide a classification of most commonly used droplet platform technologies. Then we discuss the examples of various label-free droplet detection schemes implemented for these platforms. While providing the research landscape for label-free droplet detection methods, we aim to highlight the strengths and shortcomings of each droplet platform so that a more targeted approach can be taken by researchers when selecting a droplet platform and a detection scheme for any given application.

ARFIS: Adaptive-Receiver-Based Fuzzy Inference System for Diffusion- Based Molecular Communications

2020 ◽  
Vol 16 (2) ◽  
pp. 280-289
Author(s):  
Ghalib H. Alshammri ◽  
Walid K. M. Ahmed ◽  
Victor B. Lawrence
Keyword(s):  
Fuzzy Inference System ◽  
Fuzzy Inference ◽  
Detection Threshold ◽  
Learning Rule ◽  
Optimal Number ◽  
Molecular Communication ◽  
Inference System ◽  
Detection Scheme ◽  
Adaptive Receiver ◽  
Detection Schemes

Background: The architecture and sequential learning rule-based underlying ARFIS (adaptive-receiver-based fuzzy inference system) are proposed to estimate and predict the adaptive threshold-based detection scheme for diffusion-based molecular communication (DMC). Method: The proposed system forwards an estimate of the received bits based on the current molecular cumulative concentration, which is derived using sequential training-based principle with weight and bias and an input-output mapping based on both human knowledge in the form of fuzzy IFTHEN rules. The ARFIS architecture is employed to model nonlinear molecular communication to predict the received bits over time series. Result: This procedure is suitable for binary On-OFF-Keying (Book signaling), where the receiver bio-nanomachine (Rx Bio-NM) adapts the 1/0-bit detection threshold based on all previous received molecular cumulative concentrations to alleviate the inter-symbol interference (ISI) problem and reception noise. Conclusion: Theoretical and simulation results show the improvement in diffusion-based molecular throughput and the optimal number of molecules in transmission. Furthermore, the performance evaluation in various noisy channel sources shows promising improvement in the un-coded bit error rate (BER) compared with other threshold-based detection schemes in the literature.

scholarly journals Detectivity optimization to detect of ultraweak light fluxes with an EM-CCD as binary photon counter array

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Ibtissame Khaoua ◽  
Guillaume Graciani ◽  
Andrey Kim ◽  
François Amblard
Keyword(s):  
Dynamic Range ◽  
Signal To Noise Ratio ◽  
Photon Counting ◽  
Detection Methods ◽  
Strong Nonlinearity ◽  
Wide Range ◽  
Depth Analysis ◽  
Spatially Extended ◽  
Extended Sources ◽  
Photon Counting Mode

AbstractFor a wide range of purposes, one faces the challenge to detect light from extremely faint and spatially extended sources. In such cases, detector noises dominate over the photon noise of the source, and quantum detectors in photon counting mode are generally the best option. Here, we combine a statistical model with an in-depth analysis of detector noises and calibration experiments, and we show that visible light can be detected with an electron-multiplying charge-coupled devices (EM-CCD) with a signal-to-noise ratio (SNR) of 3 for fluxes less than $$30\,{\text{photon}}\,{\text{s}}^{ - 1} \,{\text{cm}}^{ - 2}$$ 30 photon s - 1 cm - 2 . For green photons, this corresponds to 12 aW $${\text{cm}}^{ - 2}$$ cm - 2 ≈ $$9{ } \times 10^{ - 11}$$ 9 × 10 - 11 lux, i.e. 15 orders of magnitude less than typical daylight. The strong nonlinearity of the SNR with the sampling time leads to a dynamic range of detection of 4 orders of magnitude. To detect possibly varying light fluxes, we operate in conditions of maximal detectivity $${\mathcal{D}}$$ D rather than maximal SNR. Given the quantum efficiency $$QE\left( \lambda \right)$$ Q E λ of the detector, we find $${ \mathcal{D}} = 0.015\,{\text{photon}}^{ - 1} \,{\text{s}}^{1/2} \,{\text{cm}}$$ D = 0.015 photon - 1 s 1 / 2 cm , and a non-negligible sensitivity to blackbody radiation for T > 50 °C. This work should help design highly sensitive luminescence detection methods and develop experiments to explore dynamic phenomena involving ultra-weak luminescence in biology, chemistry, and material sciences.

High-sensitivity and wide-dynamic-range 10 Gbit∕s APD∕preamplifier optical receiver module

2002 ◽  
Vol 38 (13) ◽  
pp. 650 ◽  
Author(s):  
H. Matsuda ◽  
A. Miura ◽  
H. Irie ◽  
S. Tanaka ◽  
K. Ito ◽  
...  
Keyword(s):  
Dynamic Range ◽  
High Sensitivity ◽  
Optical Receiver ◽  
Wide Dynamic Range ◽  
Receiver Module

scholarly journals Electrokinetic Formation of “Microbridges” for Protein Biomarkers as Sensors

2007 ◽  
Vol 12 (5) ◽  
pp. 311-317 ◽  
Author(s):  
Vindhya Kunduru ◽  
Shalini Prasad
Keyword(s):  
Electric Fields ◽  
Microelectrode Array ◽  
Protein Detection ◽  
High Specificity ◽  
Detection Methods ◽  
Label Free ◽  
Protein Biomarkers ◽  
Detection Scheme ◽  
Polystyrene Beads ◽  
Conducting Path

We demonstrate a technique to detect protein biomarkers contained in vulnerable coronary plaque using a platform-based microelectrode array (MEA). The detection scheme is based on the property of high specificity binding between antibody and antigen similar to most immunoassay techniques. Rapid clinical diagnosis can be achieved by detecting the amount of protein in blood by analyzing the protein's electrical signature. Polystyrene beads which act as transportation agents for the immobile proteins (antigen) are electrically aligned by application of homogenous electric fields. The principle of electrophoresis is used to produce calculated electrokinetic movement among the anti-C-reactive protein (CRP), or in other words antibody funtionalized polystyrene beads. The electrophoretic movement of antibody-functionalized polystyrene beads results in the formation of “Microbridges” between the two electrodes of interest which aid in the amplification of the antigen—antibody binding event. Sensitive electrical equipment is used for capturing the amplified signal from the “Microbridge” which essentially behaves as a conducting path between the two electrodes. The technique circumvents the disadvantages of conventional protein detection methods by being rapid, noninvasive, label-free, repeatable, and inexpensive. The same principle of detection can be applied for any receptor—ligand-based system because the technique is based only on the volume of the analyte of interest. Detection of the inflammatory coronary disease biomarker CRP is achieved at concentration levels spanning over the lower microgram/milliliter to higher order nanogram/milliliter ranges.

scholarly journals Performance of Multibeam Very High Throughput Satellite Systems Based on FSO Feeder Links with HPA Nonlinearity

2020 ◽  
Author(s):  
Emna Zedini ◽  
Abla Kammoun ◽  
Mohamed-Slim Alouini
Keyword(s):  
Outage Probability ◽  
High Throughput ◽  
Direct Detection ◽  
Satellite Communications ◽  
Ergodic Capacity ◽  
Heterodyne Detection ◽  
High Signal ◽  
Free Space Optical ◽  
Asymptotic Results ◽  
Very High

Due to recent advances in laser satellite communications technology, free-space optical (FSO) links are presented as an ideal alternative to the conventional radio frequency (RF) feeder links of the geostationary satellite for next generation very high throughput satellite (VHTS) systems. In this paper, we investigate the performance of multibeam VHTS systems that account for nonlinear high power amplifiers at the transparent fixed gain satellite transponder. Specifically, we consider the forward link of such systems, where the RF user link is assumed to follow the shadowed Rician model and the FSO feeder link is modeled by the Gamma-Gamma distribution in the presence of beam wander and pointing errors where it operates under either the intensity modulation with direct detection or the heterodyne detection. Moreover, zero-forcing precoder is employed to mitigate the effect of inter-beam interference caused by the aggressive frequency reuse in the user link. The performance of the system under study is evaluated in terms of the outage probability, the average bit-error rate (BER), and the ergodic capacity that are derived in exact closed-forms in terms of the bivariate Meijer's G function. Simple asymptotic results for the outage probability and the average BER are also obtained at high signal-to-noise ratio.

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