scholarly journals A 400-Gb/s WDM-PAM4 OWC system through the free-space transmission with a water–air–water link

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Hai-Han Lu ◽  
Chung-Yi Li ◽  
Xu-Hong Huang ◽  
Poh-Suan Chang ◽  
Yu-Ting Chen ◽  
...  
Keyword(s):  
Laser Beam ◽  
Wavelength Division Multiplexing ◽  
Free Space ◽  
Transmission Rate ◽  
Pulse Amplitude ◽  
Turbid Water ◽  
Light Modulator ◽  
Total Transmission ◽  
Piped Water ◽  
Engineering Problems

AbstractA 400-Gb/s wavelength-division-multiplexing (WDM) four-level pulse amplitude modulation (PAM4) optical wireless communication (OWC) system through a 200-m free-space transmission with either an 8.8-m piped water–air–piped water link or a 6.5-m turbid water–air–turbid water link is successfully constructed. Incorporating PAM4 modulation with an 8-wavelength WDM scheme greatly increases the total transmission rate of the WDM-PAM4 OWC system to 400 Gb/s (50 Gb/s/λ × 8 λs). By adopting doublet lenses in free-space transmission, a laser beam reducer/expander and a reflective spatial light modulator (SLM) with an angle expander through the water–air–water link, good bit error rate performance and acceptable PAM4 eye diagrams are obtained. Using a reflective SLM with an angle expander not only adaptively adjusts the laser beam, but also effectively solves the oceanic engineering problems. This demonstrates WDM-PAM4 OWC system outperforms existing OWC systems through the free-space transmission with an air–water–air link because it can solve the practical engineering problems in actual oceanic environments.

scholarly journals A 400-Gb/s WDM-PAM4 OWC System Through the Free- Space Transmission With a Water-Air-Water Link

2021 ◽  
Author(s):  
Hai-Han Lu ◽  
Chung-Yi Li ◽  
Xu-Hong Huang ◽  
Poh-Suan Chang ◽  
Yu-Ting Chen ◽  
...  
Keyword(s):  
Laser Beam ◽  
Wavelength Division Multiplexing ◽  
Free Space ◽  
Transmission Rate ◽  
Pulse Amplitude ◽  
Turbid Water ◽  
Light Modulator ◽  
Total Transmission ◽  
Piped Water ◽  
Engineering Problems

Abstract A 400-Gb/s wavelength-division-multiplexing (WDM) four-level pulse amplitude modulation (PAM4) optical wireless communication (OWC) system through a 200-m free-space transmission with either an 8.8-m piped water-air-piped water link or a 6.5-m turbid water-air-turbid water link is attainably constructed. Incorporating PAM4 modulation with an 8-wavelength WDM scheme greatly increases the total transmission rate of the WDM-PAM4 OWC system to 400 Gb/s (50 Gb/s/λ × 8 λs). By employing doublet lenses in free-space transmission, a laser beam reducer/expander and a reflective spatial light modulator (SLM) with an angle expander through the water-air-water link, high bit error rate performance and acceptable PAM4 eye diagrams are obtained. Using a reflective SLM with an angle expander not only adaptively adjusts the laser beam, but also effectively solves the marine engineering problems. This demonstrated WDM-PAM4 OWC system outperforms existing OWC systems through free-space transmission with an air-water-air link due to its ability to resolve the practical engineering problems in actual marine environments.

Application scheme and performance analysis of free space optical communication technology in INMARSAT

2022 ◽  
Vol 0 (0) ◽  
Author(s):  
Zhongli Yi ◽  
Fuzhai Wang ◽  
Lianjie Jin ◽  
Yueying Zhan
Keyword(s):  
Communication Technology ◽  
Wavelength Division Multiplexing ◽  
Optical Communication ◽  
Communication System ◽  
Free Space ◽  
Transmission Rate ◽  
Free Space Optical Communication ◽  
Free Space Optical ◽  
Error Vector Magnitude ◽  
Space Optical Communication

Abstract In this study, we propose an application scheme of free space optical communication technology in INMARSAT, and propose a 1.12 Tbit/s coherent free-space optical (FSO) communication system based on wavelength division multiplexing (WDM) and polarization-multiplexing quadrature phase shift keying (PM-QPSK) modulation technology. Based on optisystem software platform, the spectrum, bit error rate (BER), received power, error vector magnitude (EVM), and receiver sensitivity of the edge and middle channels of the system are analyzed. The simulation results show that the transmission rate and channel capacity of INMARSAT communication system are greatly improved by selecting the channel spacing and transmission environment reasonably.

Performance enhancement of ultra-dense WDM over FSO hybrid optical link by incorporating MIMO technique

2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Rajneesh Kumar ◽  
Love Kumar
Keyword(s):  
Wavelength Division Multiplexing ◽  
Data Transmission ◽  
Free Space ◽  
Performance Enhancement ◽  
Transmission Rate ◽  
Weather Conditions ◽  
Optical Signal ◽  
Optical Data ◽  
Free Space Optical ◽  
Modulation Formats

AbstractFree-space optical (FSO) communication is a wireless optical data transmission technology with a high data transmission rate. It has received much attention in recent years as it is cost-effective and has license free operation. It is line of sight free-space communication technique where optical signal severely degraded from atmospheric losses especially due to weather conditions; hence it restricts the link range and data carrying capacity. Therefore, a 16-channel ultra-dense wavelength division multiplexing–free space optics (UWDM–FSO) system each having each 10 Gb/s data rate is proposed to enhance the capacity and performance of FSO system. To authenticate the performance of the proposed system, investigation for different modulation formats such as nonreturn to zero (NRZ), return to zero (RZ), carrier suppressed return to zero (CSRZ) and duo binary (DB) are reported. Further, to reduce the atmospheric interference, multiple input multiple output (MIMO) technique is integrated into the proposed system. The outcomes of MIMO–UWDM–FSO link revealed a significant improvement in the bit error rate (BER), eye diagram and Q-factor, under different weather conditions. It is also observed that NRZ modulation formats perform better than RZ, CSRZ and DB formats.

Erbium/Ytterbium-Doped Waveguide Amplifier (EYDWA) for extended reach of Wavelength Division Multiplexing based free space optics system (WDM/FSO)

2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Bentahar Attaouia ◽  
Kandouci Malika ◽  
Ghouali Samir
Keyword(s):  
Wavelength Division Multiplexing ◽  
Free Space ◽  
Cost Effective ◽  
Weather Conditions ◽  
Free Space Optical ◽  
Wavelength Division ◽  
Space Optics ◽  
Effective Implementation ◽  
Transmission Distance ◽  
The Cost

AbstractThis work is focused to carry out the investigation of wavelength division multiplexing (WDM) approach on free space optical (FSO) transmission systems using Erbium Ytterbium Doped Waveguide Amplifier (EYDWA) integrated as post-or pre-amplifier for extending the reach to 30 Km for the cost-effective implementation of FSO system considering weather conditions. Furthermore, the performance of proposed FSO-wavelength division multiplexing (WDM) system is also evaluated on the effect of varying the FSO range and results are reported in terms of Q factor, BER, and eye diagrams. It has been found that, under clear rain the post-amplification was performed and was able to reach transmission distance over 27 Km, whereas, the FSO distance has been limited at 19.5 Km by using pre-amplification.

Performance analysis of WDM free space optics transmission system using MIMO technique under various atmospheric conditions

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Kavitha Thandapani ◽  
Maheswaran Gopalswamy ◽  
Sravani Jagarlamudi ◽  
Naveen Babu Sriram
Keyword(s):  
Wavelength Division Multiplexing ◽  
Free Space ◽  
Multiple Input Multiple Output ◽  
Atmospheric Conditions ◽  
Free Space Optical ◽  
Wavelength Division ◽  
Space Optics ◽  
Space Optical Communication ◽  
Input Multiple Output ◽  
And Performance

Abstract Free Space Optical (FSO) communication has evolved as a feasible technique for wireless implementations which offers higher bandwidth capacities over various wavelengths and refers to the transmission of modulated visible beams through atmosphere in order to communicate. Wavelength Division Multiplexing (WDM) is a technology that multiplexes numerous carrier signals onto single fiber using nonidentical wavelengths and enables the efficiency of bandwidth and expanded data rate. Multiple Input Multiple Output (MIMO) is implemented to improve the quality and performance of free space optical communication in various atmospheric conditions. In this paper, a WDM-based FSO communication system is being implemented that benefits from MIMO which receives multiple copies of the signal at receiver that are independent and analyzed for various streams of data in MIMO i.e. 2 × 2, 4 × 4, 8 × 8. Various factors like BER, Quality Factor are analyzed for the WDM-based FSO communication with MIMO using the OptiSystem for various data streams of MIMO under different atmospheric conditions.

scholarly journals Differential pulse-amplitude modulation signalling for free-space optical communications

2019 ◽  
Vol 13 (4) ◽  
pp. 155-160 ◽  
Author(s):  
Mohammad Taghi Dabiri ◽  
Seyed Mohammad Sajad Sadough ◽  
Mohammad Ali Khalighi
Keyword(s):  
Amplitude Modulation ◽  
Optical Communications ◽  
Free Space ◽  
Pulse Amplitude ◽  
Differential Pulse ◽  
Pulse Amplitude Modulation ◽  
Free Space Optical

Expansion of a Focused Laser Beam in the Turbulent Atmosphere

1971 ◽  
Vol 49 (10) ◽  
pp. 1233-1248 ◽  
Author(s):  
A. D. Varvatsis ◽  
M. I. Sancer
Keyword(s):  
Laser Beam ◽  
Free Space ◽  
Turbulent Atmosphere ◽  
Focal Plane ◽  
Spot Size ◽  
Small Aperture ◽  
Forward Scatter ◽  
Green’S Theorem ◽  
Focused Beams ◽  
Weakly Dependent

This work examines the expansion of a focused laser beam in the turbulent atmosphere. The formulation is based on Green's theorem and the valid assumption that the turbulent atmosphere is a forward-scatter medium for wavelengths of interest (0.6 μ < λ < 11 μ). The main results are: (1) the spot size at the free-space focal plane in the presence of turbulence is independent of the aperture radius, and is only weakly dependent on the wavelength, (2) the focal plane can be significantly shifted for small aperture radii, short wavelengths, and long free-space focal lengths, (3) the effect of the atmosphere is pronounced only close to the free-space focus and very far away, and (4) the turbulent atmosphere has a stronger effect on weakly focused beams rather than strongly focused beams, except very close to the free-space focus, where the effect is more pronounced for strongly focused beams.

Hybrid WDM free space optical system using CSRZ and Rayleigh backscattering noise mitigation

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Rupinder Kaur ◽  
Charanjit Singh ◽  
Rajbir Kaur
Keyword(s):  
Wavelength Division Multiplexing ◽  
Free Space ◽  
Free Space Optical ◽  
Power Budget ◽  
Noise Mitigation ◽  
Wavelength Division ◽  
Rayleigh Backscattering ◽  
Beat Noise ◽  
Optical Line ◽  
Insertion Losses

Abstract Hybrid wavelength-division-multiplexing (WDM) and free space optical (FSO) access networks are getting great attention due to numerous advantages. In this work, hybrid WDM-FSO system is demonstrated for 55 km at capacity of 5 × 10 Gbit/s using compressed spectrum return to zero (CSRZ) WDM-FSO in downstream and nonreturn to zero (NRZ) in upstream for demonstrating transmitter diversity which inturn decrease the interchannel interference. For the suppression of Rayleigh backscattering (RB) interferometric beat noise, bidirectional cyclic multiplexer is employed. Cyclic multiplexer provide λ 1 to λ 5 wavelengths for optical line terminal (OLT) to ONU transmission and λ 2 to λ 6 for ONU to OLT transmission. Insertion losses of each component are considered and in the end, power budget is also calculated. Results revealed that FSO length of 780–1050 m are obtained using various WDM-FSO downstream signals and their power budget, redundant budget, maximum distance, and insertion losses also calculated.

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