scholarly journals SOA-Based Multilevel Polarization Shift On–Off Keying Transmission for Free-Space Optical Communication

Photonics ◽  
2021 ◽  
Vol 8 (4) ◽  
pp. 100
Author(s):  
Yan-Qing Hong ◽  
Do-Hoon Kwon ◽  
Jae-Young Choi ◽  
In-Ho Ha ◽  
Won-Ho Shin ◽  
...  
Keyword(s):  
Free Space ◽  
Power Efficiency ◽  
Extinction Ratio ◽  
Optical Amplifier ◽  
Intensity Level ◽  
Free Space Optical ◽  
Saturation State ◽  
Space Optical Communication ◽  
Linear State ◽  
Linear Polarizer

This paper proposes a semiconductor optical amplifier (SOA)-based multilevel polarization shift on–off keying (MPS-OOK) transmission for free-space optical (FSO) communication. At the transmitter end, the MPS-OOK signal is modulated with a constant linear state of polarization (SOP) at the high-intensity level and various SOPs at the low-intensity level in order to improve the spectral efficiency (SE) with the transmitted power efficiency. At the receiver end, first, a polarization-independent SOA was introduced to optically suppress the turbulence-induced scintillation effect and equalize the intensities of the various SOPs in the deep gain saturation state without polarization distortion. Then, a linear polarizer (LP) with a high extinction ratio (ER) was deployed to convert the equalized SOPs into a known intensity. Finally, the converted MPS-OOK signal was detected using a single photodiode (PD) and distinguished using a multilevel fixed-threshold decision (M-FTD). The proposed technique was evaluated using experiments. A Mach–Zehnder modulator (MZM)-based fading simulator was introduced to emulate the turbulence-induced scintillation effect. The experimental results demonstrated that the scintillation effect was effectively mitigated and the SE was improved by up to 2 bit/s/Hz using the proposed four-level polarization shift on–off keying (4PS-OOK) transmission.

Maximizing the Area Spanned by the Optical SNR of the 5G Using Digital Modulators and Filters

2021 ◽  
Vol 18 (3) ◽  
Author(s):  
Guruviah Karpagarajesh ◽  
Helen Anita
Keyword(s):  
Optical Communication ◽  
Free Space ◽  
Communication Systems ◽  
Power Efficiency ◽  
Filter Design ◽  
Weather Condition ◽  
Channel Noise ◽  
Free Space Optical Communication ◽  
Free Space Optical ◽  
Space Optical Communication

High security data link channels having more immunity against channel noise is the need of the century. Free Space Optical communication (FSO) is the modern technology which kick-starts it’s application in inter satellite communication, underwater communication and mobile communication to the next level of data transmission by means of complete utilisation of the allocated frequency spectrum. In Europe and Asian countries, 5G optical communication will going to expand its usage to nearly 50% in upcoming years and so bandwidth and power efficiency has to be enhanced as much as possible since the consumption rate of the users is increasing exponentially. But increasing the distance increases the attenuation in case of severe atmospheric weather condition. In this paper, 5G data rate of 50Gbps is ensured for better signal reception with maximum possible link distance between the sender and the receiver keeping variable attenuation environment. The frequency of operation is 1550nm throughout the processes. In this work, several digital modulation techniques and optical filters for receiver are designed and simulated. The better resulting modulator and filter design in terms of high Quality factor and low bit error rate are considered and is integrated with each other. The Signal to Noise Ratio (SNR) and optical SNR are calculated for the integrated design theoretically. Higher the SNR less will be BER and hence the signal connectivity can be improved in the high speed free space optical communication systems.

scholarly journals Saturation in cascaded optical amplifier free-space optical communication systems

2016 ◽  
Vol 10 (3) ◽  
pp. 71-79 ◽  
Author(s):  
Oluwatosin Jeremiah Bandele ◽  
Malcolm. S. Woolfson ◽  
Andrew Julian Phillips ◽  
Priyanka Desai
Keyword(s):  
Optical Communication ◽  
Free Space ◽  
Communication Systems ◽  
Optical Amplifier ◽  
Free Space Optical Communication ◽  
Free Space Optical ◽  
Optical Communication Systems ◽  
Space Optical Communication

An investigation of 16-QAM signal transmission over turbulent RoFSO link modeled by gamma–gamma distribution

2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Abhishek Tripathi ◽  
Shilpi Gupta ◽  
Abhilash Mandloi ◽  
Gireesh G Soni
Keyword(s):  
Gamma Distribution ◽  
Free Space ◽  
Signal Transmission ◽  
Channel Modeling ◽  
Symbol Error Rate ◽  
Average Error ◽  
60 Ghz ◽  
Free Space Optical ◽  
Error Vector Magnitude ◽  
Space Optical Communication

AbstractThis paper outlines the performance of a 10 Gbit/s rectangular 16-quadrature amplitude modulation–based radio over free space optical communication system. Here, 60 GHz radio frequency–modulated signal is propagated through a 1550-nm free space optical link. The gamma–gamma distribution is used for the channel modeling of weak to strong atmospheric turbulence. The reported constellation plots and eye patterns are attributed to impairment factors in adverse conditions of atmosphere. The evaluation is carried out that the variation in average error vector magnitude in the range of 1.45–1.63% and equivalent symbol error rate of 0.019–0.023 are obtained for a clear atmosphere compared to the turbulent link of 0.2–1 km, respectively.

Simulation modeling of free space optical communication system

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Ajay Sharma ◽  
Rajinder Singh Kaler
Keyword(s):  
Optical Communication ◽  
Free Space ◽  
Simulation Modeling ◽  
Additive White Gaussian Noise ◽  
Wireless Channel ◽  
Free Space Optical Communication ◽  
Optical Wireless ◽  
Free Space Optical ◽  
Wireless Signal ◽  
Space Optical Communication

Abstract The optical wireless communication has been designed by developing a model with the support of MATLAB simulator using Simulink where channel considered to be a free space. In this model, Additive White Gaussian Noise (AWGN) channel has used to analyze bit error rate (BER) and power loss of optical wireless signal at receiver. The consequence due to turbulence in atmosphere of free space on transmitted signal has examined. The BER and signal power have extremely ruined on rigorous atmospheric unstable condition even for a short distance in an optical wireless channel. The BER of less than 10−3 has been achieved for free space optical communication considered to be an excellent BER for FSO.

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