scholarly journals Optical Orbital Angular Momentum Demultiplexing and Channel Equalization by Using Equalizing Dammann Vortex Grating

2017 ◽  
Vol 2017 ◽  
pp. 1-9
Author(s):  
Mingyang Su ◽  
Junmin Liu ◽  
Yanliang He ◽  
Shuqing Chen ◽  
Ying Li
Keyword(s):  
Numerical Simulation ◽  
Angular Momentum ◽  
Light Intensity ◽  
Diffraction Efficiency ◽  
Orbital Angular Momentum ◽  
Bit Error Rate ◽  
Error Rate ◽  
Channel Equalization ◽  
Grating Structure

A novel equalizing Dammann vortex grating (EDVG) is proposed as orbital angular momentum (OAM) multiplexer to realize OAM signal demultiplexing and channel equalization. The EDVG is designed by suppressing odd diffraction orders and adjusting the grating structure. The light intensity of diffraction is subsequently distributed evenly in the diffraction orders, and the total diffraction efficiency can be improved from 53.22% to 82%. By using the EDVG, OAM demultiplexing and channel equalization can be realized. Numerical simulation shows that the bit error rate (BER) of each OAM channel can decrease to 10-4 when the bit SNR is 22 dB, and the intensity is distributed over the necessary order of diffraction evenly.

scholarly journals Performance analysis of an orbital angular momentum multiplexed amplify-and-forward radio relay chain with inter-modal crosstalk

2019 ◽  
Vol 6 (1) ◽  
pp. 181063 ◽  
Author(s):  
B. Allen ◽  
D. Simmons ◽  
T. D. Drysdale ◽  
J. Coon
Keyword(s):  
Angular Momentum ◽  
Performance Analysis ◽  
Orbital Angular Momentum ◽  
Bit Error Rate ◽  
Error Rate ◽  
Data Streams ◽  
Spectral Efficiency ◽  
Amplify And Forward ◽  
Parallel Data ◽  
End To End

The end-to-end spectral efficiency and bit error rate (BER) of an amplify-and-forward (AF) radio relay chain employing orbital angular momentum (OAM) multiplexing is presented. The inherent divergence of a beam carrying OAM is overcome by means of a lens. Modelled and measured inter-modal crosstalk levels are incorporated into the analysis. The results show that an end-to-end spectral efficiency of up to 8 bits s −1 Hz −1 is achievable using four OAM modes to multiplex four parallel data streams over 20 hops, provided that the detrimental effects of inter-modal crosstalk are mitigated. The spectral efficiency is expected to scale further by using more OAM modes. The BER profile along the relay chain is analysed for each of the four OAM modes.

scholarly journals THE REDUCTION OF PAPR IN OFDM BY USING NEW COMPANDING TRANSFORM

2014 ◽  
pp. 1-3
Author(s):  
T. NAGARAJU ◽  
K. RAMANAIDU
Keyword(s):  
Numerical Simulation ◽  
Theoretical Analysis ◽  
Bit Error Rate ◽  
Error Rate ◽  
Average Power ◽  
High Peak ◽  
Papr Reduction ◽  
Power Ratio ◽  
Main Drawback ◽  
Reduction Techniques

The main drawback of the OFDM is its high peak to average power ratio(PAPR).There are several PAPR reduction techniques. Among the various PAPR reduction techniques, companding transform is attractive for its simplicity and effectiveness. This paper proposes a new companding algorithm. The proposed algorithm offers an improved bit error rate and minimized out-of-band interference while reducing PAPR effectively, compared with the others. Theoretical analysis and numerical simulation are presented.

Simulated Study for OOK Modulation in the Mud Pulse Telemetry

2015 ◽  
Vol 727-728 ◽  
pp. 809-812
Author(s):  
Bo Qin Xu ◽  
Zhu Jun Zhang ◽  
Jun Wei Hu
Keyword(s):  
Numerical Simulation ◽  
Bit Error Rate ◽  
Error Rate ◽  
Pressure Wave ◽  
Signal To Noise Ratio ◽  
Signal Amplitude ◽  
Modulation Scheme ◽  
Drilling Process ◽  
Signal To Noise ◽  
Process Pressure

Mud pulse telemetry (MPT) transmits data from borehole to surface during the drilling process. Pressure wave is generated in the drilling channel and is used as carrier of the downhole data. Through numerical simulation, this paper analyzes the bit error rate (BER) of mud pulse telemetry under different signal to noise ratio (SNR) based on on-off keying (OOK) modulation scheme. By observing the effect of waveform error on BER, the allowed variation ranges in signal amplitude and period are obtained.

scholarly journals Orbital angular momentum and topological charge of a Gaussian beam with multiple optical vortices

2020 ◽  
Vol 44 (1) ◽  
pp. 34-39
Author(s):  
A.A. Kovalev ◽  
V.V. Kotlyar ◽  
D.S. Kalinkina
Keyword(s):  
Numerical Simulation ◽  
Angular Momentum ◽  
Gaussian Beam ◽  
Orbital Angular Momentum ◽  
Topological Charge ◽  
Optical Axis ◽  
Random Phase ◽  
Beam Power ◽  
Optical Vortices ◽  
Local Intensity

Here we study theoretically and numerically a Gaussian beam with multiple optical vortices with unitary topological charge (TC) of the same sign, located uniformly on a circle. Simple expressions are obtained for the Gaussian beam power, its orbital angular momentum (OAM), and TC. We show that the OAM normalized to the beam power cannot exceed the number of vortices in the beam. This OAM decreases with increasing distance from the optical axis to the centers of the vortices. The topological charge, on the contrary, is independent of this distance and equals the number of vortices. The numerical simulation corroborates that after passing through a random phase screen (diffuser) and propagating in free space, the beams of interest can be identified by the number of local intensity minima (shadow spots) and by the OAM.

scholarly journals Spin-to-orbital angular momentum conversion via light intensity gradient

Optica ◽  
2021 ◽  
Vol 8 (9) ◽  
pp. 1231
Author(s):  
Shuang-Yin Huang ◽  
Guan-Lin Zhang ◽  
Qiang Wang ◽  
Min Wang ◽  
Chenghou Tu ◽  
...  
Keyword(s):  
Angular Momentum ◽  
Light Intensity ◽  
Orbital Angular Momentum ◽  
Intensity Gradient

Bit-Error-Rate Degradation Due to Inter-Channel Crosstalk of Different Signal Format

2019 ◽  
Vol E102.B (5) ◽  
pp. 1000-1004
Author(s):  
Naruki SHINOHARA ◽  
Koji IGARASHI ◽  
Kyo INOUE
Keyword(s):  
Bit Error Rate ◽  
Error Rate
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