Performance evaluation of direct-detection coherent receiver array for free-space communications with full-link simulation

Yu, Zhaoxin; Cai, Rujun; Wu, Zijun; He, Hongwei; Jiang, Hexin; Feng, Xian; Zheng, Anrui; Chen, Junfan; Gao, Shiming

doi:10.1016/j.optcom.2019.124520

Cited by 9 publications

(6 citation statements)

References 21 publications

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“…The beam distortion results in the variation of the signal power and the shift of the signal phase, degrading the BER performance. In order to quantitatively analyze the performance of the OPC compensation, the BER of the dual-hop link with OPC correction is simulated (based on the work reported in [7] and [24]), and the BERs of the single-trip and noncompensation dual-hop FSO links are also simulated for comparison, as depicted in Figs. 4.…”

Section: Numerical Simulations and Discussionmentioning

confidence: 99%

“…4. Considering a 5 Gbit/s quadrature phase-shift keying (QPSK) signal, the signal passing through the turbulent channel is simulated based on "frozen turbulence" hypothesis [7]. The simulation is performed with different 2 containing weak, moderate and strong turbulences.…”

Section: Numerical Simulations and Discussionmentioning

confidence: 99%

“…To evaluate the influence of atmospheric turbulence imposed on the laser beam, the phase distortions can be physically modelled and numerically simulated by using the phase screen method [7]. The total propagation distance is sectioned into smaller turbulent layers, and each layer is considered as a unit-amplitude thin phase screen.…”

Section: Principles Of the Turbulence Corrected Methodsmentioning

confidence: 99%

“…In order to reduce the effect of atmospheric turbulences, variety of mitigation techniques have been proposed including aperture averaging technique [6], diversity technique [7], advanced modulation scheme [8], and adaptive optics [3]. Moreover, adaptive optics (AO) are commonly used to compensate for the turbulence-induced wavefront phase aberrations in coherent FSO communication link [9].…”

Section: Introductionmentioning

confidence: 99%

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Free-Space Communication Turbulence Compensation by Optical Phase Conjugation

et al. 2020

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A new scheme is proposed to mitigate the atmospheric turbulence effect in coherent free-space optical (FSO) communications by employing optical phase conjugation (OPC) to compensate the signal distortion. The compensation performance of the dual-hop FSO transmission link is simulated using the phase screen method for quadrature phase-shift keying (QPSK) signals. The results show that the bite error rate (BER) can be effectively reduced and the OPC correction is tightly affected by the OPC receiving aperture in strong turbulence regimes. The dual-hop FSO link with the OPC correction is experimentally demonstrated in a turbulence-tunable atmospheric cell, where the OPC is achieved by using degenerate four-wave mixing (DFWM) in a 110-m-long highly nonlinear fiber. At the BER of × − , the power penalty for dual-hop link with OPC correction decreases about 1.2 dB and 2 dB compared with the single-trip link and the non-compensation dual-hop link. The result demonstrates that the OPC unit can improve the performances of the coherent FSO communication, and it has the potential to be extended to higher-order modulation formats and higher bit rate processing.

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Section: Numerical Simulations and Discussionmentioning

confidence: 99%

Section: Numerical Simulations and Discussionmentioning

confidence: 99%

Section: Principles Of the Turbulence Corrected Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Free-Space Communication Turbulence Compensation by Optical Phase Conjugation

et al. 2020

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“…where s OFDM (t) = ∑ N k=1 x k exp(j2π f k t) is the OFDM signal sent by the transmitter, N is the number of sub-carriers, f k is the frequency of the kth sub-carrier, x k is the complex data in the kth sub-carrier which is modulated in a QPSK format, y is the receiving signal at the receiver, n is the additive white Gaussian noise (AWGN), and h is the influence coefficient caused by the atmospheric turbulence channel. As shown in Figure 1, the OFDM-FSO system's performance can be evaluated by using a split-step beam propagation method based on phase screen theory [22]. The transmission distance L is divided into several segments, each of which has two parts: a vacuum transmission link of length ∆z and a phase screen regardless of thickness.…”

Section: System Structure and Channel Modelmentioning

confidence: 99%

Performance Improvement of the Free-Space Optical Communication Link Using Spatial Diversity Reception-Assisted OFDM Signals

et al. 2022

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Orthogonal frequency division multiplexing (OFDM) technology is presented for use in free-space optical (FSO) communications accompanied by the spatial diversity reception. Using quadrature phase shift keying (QPSK) modulation formats, the OFDM signals show robustness to support high spectral efficiency and compatibility with the spatial diversity reception to improve receiver sensitivity. Compared with the single-carrier QPSK signal, the OFDM-QPSK signal with 64 sub-carriers can reduce the BER from 2.87 × 10−3 to 2.98 × 10−4 at the SNR of 6 dB. Using a two-aperture spatial diversity reception with OFDM, the BER can be reduced from 2.45 × 10−3 of a single receiver to 6.10 × 10−4 under moderate turbulence conditions. Under strong turbulence, the BER of the single receiver is 2.14 × 10−2. It can be improved to 1.16 × 10−3 by using four-aperture receivers, and even 6.87 × 10−4 by using six-aperture receivers. The optimized aperture number should be selected according to channel conditions.

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