The analysis of high-capacity quantum secure direct communication using polarization and orbital angular momentum of photons

2019 ◽  
Vol 34 (02) ◽  
pp. 2050017 ◽  
Author(s):  
Lin-Yi Li ◽  
Tie-Jun Wang ◽  
Chuan Wang
Keyword(s):  
Angular Momentum ◽  
Quantum Information ◽  
Channel Capacity ◽  
Orbital Angular Momentum ◽  
Quantum Communication ◽  
High Capacity ◽  
Quantum Secure Direct Communication ◽  
Noise Elimination ◽  
Long Distance ◽  
Direct Communication

Higher channel capacity and noise elimination are the key requirements for the implementation of long-distance quantum communication. As the additional degrees of freedom (DoF) of photons can be employed to achieve higher channel capacity and security beyond the polarizations DoF of photons, the photonic qubits are always employed as the flying qubits in quantum communication and quantum information processing. Here, exploiting the multiple DoFs of photons, we present an efficient quantum secure direct communication protocol based on the coding and manipulation of qubits on both the polarization and the orbital angular momentum of photons. Also, the numerical simulation is studied to further clarify the improvement of the channel capacity and the security. It is found that the channel capacity and the error rate (caused by eavesdropping) of the QSDC protocol which encoded on the polarization DoF and the OAM DoF is significantly higher than that of coding on only polarization DoF. We believe this work could provide more evidence for the applications of higher-dimensional qubits in quantum information science.

scholarly journals Modal coupling and crosstalk due to turbulence and divergence on free space THz links using multiple orbital angular momentum beams

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Zhe Zhao ◽  
Runzhou Zhang ◽  
Hao Song ◽  
Kai Pang ◽  
Ahmed Almaiman ◽  
...  
Keyword(s):  
Angular Momentum ◽  
Atmospheric Turbulence ◽  
Channel Capacity ◽  
Orbital Angular Momentum ◽  
Beam Waist ◽  
Modal Coupling ◽  
Divergence Effect ◽  
Power Leakage ◽  
Calm Weather ◽  
Bad Weather

AbstractOrbital-angular-momentum (OAM) multiplexing has been utilized to increase the channel capacity in both millimeter-wave and optical domains. Terahertz (THz) wireless communication is attracting increasing attention due to its broadband spectral resources. Thus, it might be valuable to explore the system performance of THz OAM links to further increase the channel capacity. In this paper, we study through simulations the fundamental system-degrading effects when using multiple OAM beams in THz communications links under atmospheric turbulence. We simulate and analyze the effects of divergence, turbulence, limited-size aperture, and misalignment on the signal power and crosstalk of THz OAM links. We find through simulations that the system-degrading effects are different in two scenarios with atmosphere turbulence: (a) when we consider the same strength of phasefront distortion, faster divergence (i.e., lower frequency; smaller beam waist) leads to higher power leakage from the transmitted mode to neighbouring modes; and (b) however, when we consider the same atmospheric turbulence, the divergence effect tends to affect the power leakage much less, and the power leakage increases as the frequency, beam waist, or OAM order increases. Simulation results show that: (i) the crosstalk to the neighbouring mode remains < − 15 dB for a 1-km link under calm weather, when we transmit OAM + 4 at 0.5 THz with a beam waist of 1 m; (ii) for the 3-OAM-multiplexed THz links, the signal-to-interference ratio (SIR) increases by ~ 5–7 dB if the mode spacing increases by 1, and SIR decreases with the multiplexed mode number; and (iii) limited aperture size and misalignment lead to power leakage to other modes under calm weather, while it tends to be unobtrusive under bad weather.

scholarly journals Ring-Core Photonic Crystal Fiber of Terahertz Orbital Angular Momentum Modes with Excellence Guiding Properties in Optical Fiber Communication

Photonics ◽  
2021 ◽  
Vol 8 (4) ◽  
pp. 122
Author(s):  
Fahad Ahmed Al-Zahrani ◽  
Md. Anowar Kabir
Keyword(s):  
Angular Momentum ◽  
Photonic Crystal ◽  
Photonic Crystal Fiber ◽  
Orbital Angular Momentum ◽  
High Capacity ◽  
Optical Fiber Communication ◽  
Fused Silica ◽  
Confinement Loss ◽  
Crystal Fiber ◽  
Ring Core

The orbital angular momentum (OAM) of light is used for increasing the optical communication capacity in the mode division multiplexing (MDM) technique. A novel and simple structure of ring-core photonic crystal fiber (RC-PCF) is proposed in this paper. The ring core is doped by the Schott sulfur difluoride material and the cladding region is composed of fused silica with one layer of well-patterned air-holes. The guiding of Terahertz (THz) OAM beams with 58 OAM modes over 0.70 THz (0.20 THz–0.90 THz) frequency is supported by this proposed RC-PCF. The OAM modes are well-separated for their large refractive index difference above 10−4. The dispersion profile of each mode is varied in the range of 0.23–7.77 ps/THz/cm. The ultra-low confinement loss around 10−9 dB/cm and better mode purity up to 0.932 is achieved by this RC-PCF. For these good properties, the proposed fiber is a promising candidate to be applied in the THz OAM transmission systems with high feasibility and high capacity.

scholarly journals Perspectives on advances in high-capacity, free-space communications using multiplexing of orbital-angular-momentum beams

APL Photonics ◽  
2021 ◽  
Vol 6 (3) ◽  
pp. 030901
Author(s):  
Alan E. Willner ◽  
Zhe Zhao ◽  
Cong Liu ◽  
Runzhou Zhang ◽  
Haoqian Song ◽  
...  
Keyword(s):  
Angular Momentum ◽  
Orbital Angular Momentum ◽  
Free Space ◽  
High Capacity ◽  
Space Communications

scholarly journals High-capacity millimetre-wave communications with orbital angular momentum multiplexing

2014 ◽  
Vol 5 (1) ◽  
Author(s):  
Yan Yan ◽  
Guodong Xie ◽  
Martin P. J. Lavery ◽  
Hao Huang ◽  
Nisar Ahmed ◽  
...  
Keyword(s):  
Angular Momentum ◽  
Orbital Angular Momentum ◽  
High Capacity ◽  
Millimetre Wave

Two semi-quantum secure direct communication protocols based on Bell states

2019 ◽  
Vol 34 (01) ◽  
pp. 1950004 ◽  
Author(s):  
Yuhua Sun ◽  
Lili Yan ◽  
Yan Chang ◽  
Shibin Zhang ◽  
Tingting Shao ◽  
...  
Keyword(s):  
Quantum Communication ◽  
Communication Protocols ◽  
Quantum Secure Direct Communication ◽  
Bell States ◽  
Secret Key ◽  
Direct Communication ◽  
Quantum Protocols ◽  
Shared Secret ◽  
Full Quantum ◽  
Qubit Efficiency

Quantum secure direct communication allows one participant to transmit secret messages to another directly without generating a shared secret key first. In most of the existing schemes, quantum secure direct communication can be achieved only when the two participants have full quantum ability. In this paper, we propose two semi-quantum secure direct communication protocols to allow restricted semi-quantum or “classical” users to participate in quantum communication. A semi-quantum user is restricted to measure, prepare, reorder and reflect quantum qubits only in the classical basis [Formula: see text]. Both protocols rely on quantum Alice to randomly prepare Bell states, perform Bell basis measurements and publish the initial Bell states, but the semi-quantum Bob only needs to measure the qubits in classical basis to obtain secret information without quantum memory. Security and qubit efficiency analysis have been given in this paper. The analysis results show that the two protocols can avoid some eavesdropping attacks and their qubit efficiency is higher than some current related quantum or semi-quantum protocols.

High-capacity spatial-division multiplexing with orbital angular momentum based on multi-ring fiber

2019 ◽  
Vol 21 (5) ◽  
pp. 055601 ◽  
Author(s):  
Duo Deng ◽  
Yan Li ◽  
Hua Zhao ◽  
Yanhua Han ◽  
Jingfu Ye ◽  
...  
Keyword(s):  
Angular Momentum ◽  
Orbital Angular Momentum ◽  
High Capacity ◽  
Spatial Division Multiplexing
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