scholarly journals Laboratory Measurements of the Influence of Turbulence Intensity on the Instantaneous-Fading Reciprocity of Bidirectional Atmospheric Laser Propagation Link

2021 ◽  
Vol 11 (8) ◽  
pp. 3499
Author(s):  
Yi Liu ◽  
Zhi Liu ◽  
Yidi Chang ◽  
Yang Liu ◽  
Huilin Jiang
Keyword(s):  
Correlation Coefficient ◽  
Atmospheric Turbulence ◽  
Turbulence Intensity ◽  
Optical Signal ◽  
Optical Channel ◽  
Optical Signals ◽  
Optical Channels ◽  
Laser Propagation ◽  
Hot Air ◽  
Air Convection

The reciprocity of the atmospheric turbulence channel in the bidirectional atmospheric laser propagation link is experimentally tested. The bidirectional transceiving coaxial atmospheric laser propagation link is built by using a hot air convection-type atmospheric turbulence emulation device with adjustable turbulence intensity. The influence of different turbulence intensities on the instantaneous-fading correlation of channel is analyzed by the spot characteristics. When there is no atmospheric turbulence in the bidirectional transceiving coaxial atmospheric laser propagation link, the value of channel instantaneous fading correlation coefficient was merely 0.023, which indicates we did not find any reciprocity in the optical channel. With the increment in turbulence intensity, the channel instantaneous fading correlation coefficient presented a constant increasing trend and then tended to be stable around 0.9 in the end. At this moment, the similarity of the instantaneous change trends for these two receiving terminal optical signals, and the consistency of their probability density function, indicates that there is good reciprocity between the bidirectional atmospheric turbulence optical channels. With the increase in the optical signal scintillation factor, we can obtain the result where the correlation coefficient value decreases accordingly.

Analysis on the Effects of Atmospheric Turbulence on Line-of-Sight Ultraviolet Communication System Performance

2014 ◽  
Vol 1014 ◽  
pp. 102-105
Author(s):  
Yong Wang ◽  
Meng Ying Su
Keyword(s):  
Information Transmission ◽  
Atmospheric Turbulence ◽  
Turbulence Intensity ◽  
Communication System ◽  
Transmission Rate ◽  
Optical Signals ◽  
Communication System Performance ◽  
Intensity Changes ◽  
Ultraviolet Communication ◽  
Ber Performance

In the ultraviolet communication system, optical signals being transmitted are not only attenuated in energy, but also affected by the atmospheric turbulence. The effects of atmospheric turbulence intensity and information transmission rate on the BER performance of UV communication system are analyzed and simulated in this paper. It can be found that when the atmospheric turbulence intensity changes from weak to strong, the BER performance deteriorates along, and under the certain atmospheric turbulence intensity, information transmission rate will also have an impact on the system BER performance, the information transmission rate becomes faster, the BER performance gets worse.

Characteristic Analysis of Hot Air Convection Atmospheric Turbulence simulator

2015 ◽  
Vol 35 (s1) ◽  
pp. s101004 ◽  
Author(s):  
倪小龙 Ni Xiaolong ◽  
宋卢军 Song Lujun ◽  
付强 Fu Qiang ◽  
刘艺 Liu Yi ◽  
李小伟 Li Xiaowei ◽  
...  
Keyword(s):  
Atmospheric Turbulence ◽  
Characteristic Analysis ◽  
Hot Air ◽  
Air Convection

scholarly journals Development, research and metrological analysis of the measuring channel of a fiber-optic sensor for fluid flow parameters used in information-measuring systems

2018 ◽  
Vol 245 ◽  
pp. 09016
Author(s):  
Elena Badeeva ◽  
Elena Shachneva ◽  
Alexandr Udalov ◽  
Tatiana Murashkina
Keyword(s):  
Measurement Errors ◽  
Fiber Optic ◽  
Optical Signal ◽  
Measuring Channel ◽  
Fiber Optic Sensor ◽  
Optical Channel ◽  
Metrological Analysis ◽  
Optical Signals ◽  
New Variant ◽  
Liquid Flows

The article proposes a device for measuring parameters of liquid flows (volume and velocity) (FOSLFP). A physico-mathematical model of optical signal conversion in a fiber-optic flux transducer of the proposed sensor is developed, in which the perceiving element is a truncated cylinder mounted on the inner surface of the bellows, experiencing angular bending during measurements. The conversion of optical signals is carried out using a two-way mirror plate mounted on the outer surface of the bellows in an open fiber optical channel. A circuit-analytical model of a new variant of a differential circuit for converting optical signals to a FOSLFP was developed, in accordance with which a metrological model of the sensor was developed to determine the possible sources of measurement errors. The nominal and real functions of the FOSLFP transformation were derived, the additive and multiplicative components of the errors of the two measuring channels of the sensor and the ways to reduce them were determined.

scholarly journals The Optical Signal-to-Crosstalk Ratio for the MBA(N, e, g) Switching Fabric †

Sensors ◽  
2021 ◽  
Vol 21 (4) ◽  
pp. 1534
Author(s):  
Remigiusz Rajewski
Keyword(s):  
Optical Switching ◽  
Essential Feature ◽  
Optical Signal ◽  
Point Of View ◽  
Signal Quality ◽  
Switching Networks ◽  
Optical Elements ◽  
Optical Signals ◽  
Switching Fabric

The banyan-type switching networks, well known in switching theory and called the logdN switching fabrics, are composed of symmetrical switching elements of size d×d. In turn, the modified baseline architecture, called the MBA(N,e,g), is only partially built from symmetrical optical switching elements, and it is constructed mostly from asymmetrical optical switching elements. Recently, it was shown that the MBA(N,e,g) structure requires a lower number of passive as well as active optical elements than the banyan-type switching fabric of the same capacity and functionality, which makes it an attractive solution. However, the optical signal-to-crosstalk ratio for the MBA(N,e,g) was not investigated before. Therefore, in this paper, the optical signal-to-crosstalk ratio in the MBA(N,e,g) was determined. Such crosstalk influences the output signal’s quality. Thus, if such crosstalk is lower, the signal quality is better. The switching fabric proposed in the author’s previous work has lower optical signal losses than a typical Beneš and banyan-type switching networks of this same capacity and functionality, which gives better quality of transmitted optical signals at the switching node’s output. The investigated MBA(N,e,g) architecture also contains one stage fewer than banyan-type network of the same capacity, which is an essential feature from the optical switching point of view.

Phase screen simulations of laser propagation through non-Kolmogorov atmospheric turbulence

2011 ◽  
Author(s):  
V. S. Rao Gudimetla ◽  
Richard B. Holmes ◽  
Thomas C. Farrell ◽  
Jacob Lucas
Keyword(s):  
Atmospheric Turbulence ◽  
Phase Screen ◽  
Laser Propagation

Transmission of Signals Using White LEDs for VLC Application

MRS Advances ◽  
2016 ◽  
Vol 1 (55) ◽  
pp. 3661-3666 ◽  
Author(s):  
P. Louro ◽  
V. Silva ◽  
J. Costa ◽  
M. A. Vieira ◽  
M. Vieira
Keyword(s):  
Optical Filter ◽  
Visible Light Communication ◽  
Indoor Navigation ◽  
Optical Signals ◽  
White Leds ◽  
Indoor Location ◽  
Optical Channels ◽  
Wavelength Sensitivity ◽  
Location Algorithm ◽  
The Individual

ABSTRCTIn this paper a photodetector working as an active optical filter device is used to detect modulated visible optical signals for applications based on Visible Light Communication (VLC). The proposed application demonstrates the viability of indoor positioning using VLC technology established by the modulation of indoor ultra-bright RGB white LEDs. The signals of the internal red and blue chips of the white LEDs were modulated at specific frequencies and the generated photocurrent was measured by a pin-pin photodetector based on a-SiC:H/a-Si:H. This device operates as a visible optical filter with controlled wavelength sensitivity through the use of adequate optical biasing light. Thus it is able to detect different wavelengths which allow the detection of the individual components of the tri-chromatic white LED. This possibility is the basis for the indoor location algorithm. We demonstrate the possibility of decoding four transmission optical channels supplied by two different wavelengths of white LEDs modulated under different bit sequences. The identification of the signals received by the photodetector allows the location identification of the photodetector position and supplies indoor navigation.

Theoretical Methods of Images Processing in Optoelectronic Systems

Biometrics ◽  
2017 ◽  
pp. 361-381
Author(s):  
Tatyana Strelkova ◽  
Vladimir Kartashov ◽  
Alexander P. Lytyuga ◽  
Alexander I. Strelkov
Keyword(s):  
Mathematical Model ◽  
Signal To Noise Ratio ◽  
Detection Algorithm ◽  
Optical Signal ◽  
Optoelectronic System ◽  
Output Plane ◽  
Mean Values ◽  
Optical Signals ◽  
Images Processing ◽  
Detection Characteristics

The chapter covers development of mathematical model of signals in output plane of optoelectronic system with registration of optical signals from objects. Analytical forms for mean values and dispersion of signal and interference components of photo receiver response are given. The mathematical model can be used as a base with detection algorithm development for optical signal from objects. An algorithm of signals' detection in output plane of optoelectronic system for the control is offered. The algorithm is synthesized taking into account corpuscular and statistical properties of optical signals. Analytical expressions for mean values and signal and noise components dispersion are cited. These expressions can be used for estimating efficiency of the offered algorithm by the criterion of detection probabilistic characteristics and criterion of signal/noise relation value. The possibility of signal detection characteristics improvement with low signal-to-noise ratio is shown.

Experiment and Analytical Studies Jujube Drying by the Solar Assisted Convection Drying

Solar Energy ◽  
2004 ◽  
Author(s):  
Minghu Cui
Keyword(s):  
Solar Energy ◽  
Drying Process ◽  
Drying Characteristics ◽  
Hot Air ◽  
Air Convection ◽  
Jujube Fruit ◽  
Save Energy ◽  
Drying Curves ◽  
Mass Transfers ◽  
And Behavior

An experimental setup, a mini-cabinet with reflector at its top, has been designed to study the drying process of jujube fruit by the convection and the solar radiation with hot air convection. The research experimentally investigated the drying characteristics and behavior of heat and mass transfer. Also, drying curves were analyzed. It demonstrated that solar energy could play an important role in promoting heat and mass transfers and saves energy consumed. The optimum conditions of appropriated temperature and humidity were obtained to save energy in solar energy convection drying process.

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