scholarly journals Analysis of Free-Space Optics Development

2017 ◽  
Vol 24 (4) ◽  
pp. 653-674 ◽  
Author(s):  
Janusz Mikołajczyk ◽  
Zbigniew Bielecki ◽  
Maciej Bugajski ◽  
Józef Piotrowski ◽  
Jacek Wojtas ◽  
...  
Keyword(s):  
Hybrid Systems ◽  
Optical Communications ◽  
Free Space ◽  
Limiting Factors ◽  
Optical Data ◽  
Free Space Optics ◽  
Free Space Optical ◽  
Space Optics ◽  
Data Links ◽  
Further Development

AbstractThe article presents state of work in technology of free-space optical communications (Free Space Optics − FSO). Both commercially available optical data links and their further development are described. The main elements and operation limiting factors of FSO systems have been identified. Additionally, analyses of FSO/RF hybrid systems application are included. The main aspects of LasBITer project related to such hybrid technology for security and defence applications are presented.

scholarly journals An Overview of Free Space Optics with Quantum Cascade Lasers

2014 ◽  
Vol 60 (3) ◽  
pp. 259-264 ◽  
Author(s):  
Janusz Mikołajczyk
Keyword(s):  
Free Space ◽  
Open Space ◽  
Quantum Cascade Lasers ◽  
Optical Systems ◽  
Optical Data ◽  
Free Space Optics ◽  
Free Space Optical ◽  
Quantum Cascade ◽  
Space Optics ◽  
Cascade Lasers

Abstract The article presents an overview of the work on quantum cascade lasers application in free space optical systems (Free Space Optics - FSO). There are discussed the main issues of the open-space laser communications and their practical construction. Comparative analyses of each FSO technology were performed. Brief description of quantum cascade (QC) lasers and some developments related to the use of these lasers in optical data link are also presented. In summary, the constructed models of FSO links with QC lasers are characterized.

Mitigation of Atmospheric Turbulences Using Mode Division Multiplexing based on Decision Feedback Equalizer for Free Space Optics

2020 ◽  
Vol 41 (2) ◽  
pp. 185-193 ◽  
Author(s):  
Abdullah Almogahed ◽  
Angela Amphawan ◽  
Yousef Fazea
Keyword(s):  
Free Space ◽  
Minimum Mean Square Error ◽  
Decision Feedback ◽  
Free Space Optics ◽  
Decision Feedback Equalizer ◽  
Free Space Optical ◽  
Space Optics ◽  
Link Distance ◽  
Mode Division Multiplexing ◽  
Simulation Results

AbstractIn mode division multiplexing (MDM) free space optical (FSO) communication system, the atmospheric turbulences such as fog, rain, and haze cause adverse effects on system performance. This paper investigates the mitigation of atmospheric turbulences of FSO using MDM and decision feedback equalizer (DFE) with minimum mean square error (MMSE) algorithm. The implementation of the MMSE algorithm is used to optimize both the feedforward and the feedback filter coefficients of DFE. The proposed system comprises three parallel 2.5Gbit/s channels using Hermite–Gaussian modes. A data rate of 7.5Gbit/s over 40 m, 800 m, 1400 m, and 2km under medium fog, rain, haze, and clear weather, respectively, has been achieved. In addition, it is noticed that the link distance is reduced while increasing the attenuation. The simulation results revealed that a DFE improves the performance MDM FSO system while maintaining high throughput and desired low bit error rate.

scholarly journals Investigations of Free Space Optical Communications Under Real-World Atmospheric Conditions

2020 ◽  
Vol 116 (1) ◽  
pp. 475-490 ◽  
Author(s):  
Tobias Siegel ◽  
Shun-Ping Chen
Keyword(s):  
Optical Communications ◽  
Free Space ◽  
Communication Systems ◽  
New Technologies ◽  
Weather Conditions ◽  
Optical Systems ◽  
Limiting Factors ◽  
Atmospheric Conditions ◽  
Free Space Optical ◽  
Atmospheric Channel

AbstractDue to the increasing demand for higher bandwidth in modern communication systems, conventional networks are continuously expanded with new technologies to improve coverage. Free space optical communications (FSOC) shows some significant advantages concerning system setup time in comparison with the classical fiber optical systems on one hand, substantial spectral bandwidth and performances in comparison with the wireless systems under certain conditions on the other hand. This makes this technology not only a reasonable extension for metropolitan area networks but also provides the capability to set up a network after an outage in case of natural disaster quickly. But transmitting data by using FSOC involves some limiting factors that have to be considered prior to each installation. Since the atmospheric channel is not static, the influence of changing weather conditions or industrial smog have a significant impact on the available bitrate. A simulation platform is developed and presented in this paper for investigation of FSOC considering these circumstances. Regarding the atmospheric channel, turbulence, distance-dependent beam divergence, and applied modulation schemes, a general overview of the capabilities is presented and discussed. The insight of this paper should help to make a decision under which preconditions either the FSOC provides a meaningful application possibility, or the limiting factors become too crucial and other technologies must be considered.

scholarly journals The Role and Challenges of Free-space Optical Systems

2014 ◽  
Vol 35 (4) ◽  
Author(s):  
Sushank Chaudhary ◽  
Angela Amphawan
Keyword(s):  
Free Space ◽  
Satellite Communications ◽  
Radio Networks ◽  
Optical Systems ◽  
Free Space Optics ◽  
Free Space Optical ◽  
Optical Carrier ◽  
High Data ◽  
Space Optics ◽  
Data Rates

AbstractComplementing wireless radio networks with free-space optics (FSO) achieves high data rates by modulating radio subcarriers over an optical carrier without expensive optical fiber cabling, enabling a pervasive platform for reaching underserved areas. In this paper, we review the main features of FSO for terrestrial and inter-satellite communications. Simulations of 1 Gbps data transmission through FSO links in both terrestrial and inter-satellite communications have been investigated to highlight potential atmospheric challenges in FSO.

scholarly journals Modulation Techniques of Free Space Optics using Various Link Ranges

2019 ◽  
Vol 9 (2) ◽  
pp. 2952-2955
Keyword(s):  
Free Space ◽  
Free Space Optics ◽  
Free Space Optical ◽  
Optical Links ◽  
Space Optics ◽  
Data Rates ◽  
Modulation Techniques ◽  
Efficient Communication ◽  
Link Budget ◽  
Attenuation Values

Free space optics is the present trend, which enables the communication to achieve the expected data rates for the increasing user demands. The utility of FSO in free space medium enables higher data rates than the conventional microwave links for efficient communication. Several researchers have performed the analysis of free space optics by use of different modulation techniques and optimization of the link budget in free space optical links. In this work, CW laser transmitting source ranging to 10dB of output level, link ranges of 500, 1000 and 1500 mts with attenuation values of 0.2, 0.7 and 0.9 dB/Km respectively are considered. The analysis of free space optics is carried out by using various modulation techniques such as ASK, PSK, FSK, MZ, EA, Dual Drive MZ and it is observed that Dual Drive MZ modulation performs well when compared with the other modulation techniques.

scholarly journals Analysis of Rain Effects on Terrestrial Free Space Optics based on Data Measured in Tropical Climate

2012 ◽  
Vol 12 (5) ◽  
Author(s):  
Suriza Ahmad Zabidi ◽  
Md. Rafiqul Islam ◽  
Wajdi Al-Khateeb ◽  
Ahmed Wathik Naji
Keyword(s):  
Fiber Optics ◽  
Free Space ◽  
Prediction Models ◽  
Tropical Climate ◽  
Rain Attenuation ◽  
Free Space Optics ◽  
Tropical Region ◽  
Communication Link ◽  
Free Space Optical ◽  
Space Optics

Free Space Optics (FSO) shows a great alternative as the solution for last mile problem where fiber optics is unavailable due to deployment time and cost constraint.  However, the feasibility of using FSO system as communication link very much depends on local weather.  Since tropical region experiences heavy rainfall, rain with high intensity is expected to affect the FSO link severely. Few prediction models have been proposed by ITU-R based on France and Japan’s measurement. This paper has compared  rain attenuation predicted by  models and  data measured in Malaysia over Free Space Optical links for one year period. Prediction models are clearly unable to predict attenuation measured in tropical climate. ABSTRAK: Wayarles optik menjadi alternatif sebagai satu penyelesaian kepada masalah kesesakan terutama diakhir sesuatu talian dimana ianya tidak dapat diselesaikan dengan menggunakan gentian fiber akibat daripada kekangan masa pemasangan dan masalah kewangan.  Walaubagaimanapun, kejayaan untuk menggunakan wayarless optic ini amat bergantung kepada keadaan cuaca di sesuatu tempat.  Di rantau tropika  hujan lebat sentiasa dialami, oleh itu hujan dengan kepadatan tinggi adalah dijangkakan lebih memberi kesan kepada talian wayarles optic ini. Beberapa model yang telah dicadangkan oleh ITU-R berlandaskan kepada pengumpulan data yang dibuat di Perancis dan Jepun.  Kertas kajian ini akan membandingkan antara model-model yang telah digunapakai dengan data yang dikumpulkan di Malaysia selama setahun.  Jelasnya model yang telah digunapakai tidak dapat digunakan secara berkesan di rantau tropika.KEYWORDS: free space optics; rainfall rate; rain attenuation

scholarly journals Performance of geometrical effect in wavelength filtrate detection using 10gbps data rate for free space optical communication system

2019 ◽  
Vol 13 (2) ◽  
pp. 575
Author(s):  
M.F Talib ◽  
Anuar M.S ◽  
C.B.M. Rashidi
Keyword(s):  
Error Rate ◽  
Free Space ◽  
Simulation Analysis ◽  
Data Rate ◽  
Free Space Optics ◽  
Free Space Optical ◽  
Absolute Value ◽  
Space Optics ◽  
Space Optical Communication ◽  
Geometrical Effect

<span>In this paper, the analysis of comparison between proposed detection called as Wavelength Filtrate Detection with existing detection have been analyzed to determine the best system performance in term of power received and bit error rate (BER). The analysis focus on the geometrical effect of aperture receiver and beam divergence. The performance of Free Space Optics is validated through simulation analysis using parameter 10Gbps data rate and in 14dB/km atmospheric attenuation. This analysis shows that Wavelength Filtrate Detection increase the power received of 6dBm and improve the absolute value of error rate 10-9 in acceptable threshold required by (ITR-U) as much as 50% compare to others existing detection</span>

Free-space optical data links based on coaxial sidelobemodified optical vortices

2015 ◽  
Vol 13 (10) ◽  
pp. 100502-100506 ◽  
Author(s):  
Meng Zhang Meng Zhang ◽  
Ping Jia Ping Jia ◽  
Yuru Li Yuru Li ◽  
Ting Lei Ting Lei ◽  
Zhaohui Li Zhaohui Li ◽  
...  
Keyword(s):  
Free Space ◽  
Optical Data ◽  
Optical Vortices ◽  
Free Space Optical ◽  
Data Links

scholarly journals Performance Analysis of Single and Multiple Channel FSO System under Turbulent Conditions Using Various Models

2018 ◽  
Vol 7 (3.12) ◽  
pp. 14 ◽  
Author(s):  
A Sree Madhuri ◽  
M Venkata Narayana ◽  
Govardhani. Immadi
Keyword(s):  
Free Space ◽  
New Technologies ◽  
Rain Attenuation ◽  
Limiting Factors ◽  
Free Space Optics ◽  
Video Communications ◽  
Tropical Regions ◽  
Multiple Channel ◽  
Space Optics ◽  
Microwave Communications

Telecommunications occupying the major part of research across the world, has become a part and parcel of present day human’s life. As a part of research many new technologies emerged among which free space optics was found to be highly efficient and a competent technology. So, replacing the present microwave communications, in future free space optics provides many advantages like higher bandwidth, higher data rate (capable of sending up to 1.25 Gbps of data, voice, and video communications simultaneously through the air), low bit error rate and license free long-range communications etc. As a known fact that every coin has two sides, free space optics besides providing the above advantages also suffers from many range limiting factors like fog, beam dispersion, atmospheric absorption, rain attenuation, snow, terrestrial scintillation amongst which rain, scintillation and fog are popular in tropical regions like India. In this paper the effect of rain on FSO link is analysed in 1/1 and 4/4 channel cases and the results were analysed.  

Method for simulating free space optical data links for personnel applications

2013 ◽  
Author(s):  
Kiron Mateti ◽  
Brandon R. Clarke ◽  
Ean J. Seals ◽  
Gregory J. Petty ◽  
Hoang Q. Tran ◽  
...  
Keyword(s):  
Free Space ◽  
Optical Data ◽  
Free Space Optical ◽  
Data Links
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