scholarly journals Orbital Angular Momentum-based Space Division Multiplexing for High-capacity Underwater Optical Communications

2016 ◽  
Vol 6 (1) ◽  
Author(s):  
Yongxiong Ren ◽  
Long Li ◽  
Zhe Wang ◽  
Seyedeh Mahsa Kamali ◽  
Ehsan Arbabi ◽  
...  
Keyword(s):  
Angular Momentum ◽  
Orbital Angular Momentum ◽  
Optical Communications ◽  
High Capacity ◽  
Space Division Multiplexing ◽  
Space Division

scholarly journals Adaptive demodulation by deep-learning-based identification of fractional orbital angular momentum modes with structural distortion due to atmospheric turbulence

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Youngbin Na ◽  
Do-Kyeong Ko
Keyword(s):  
Angular Momentum ◽  
Deep Learning ◽  
High Resolution ◽  
Atmospheric Turbulence ◽  
Orbital Angular Momentum ◽  
Optical Communications ◽  
Recognition Performance ◽  
High Capacity ◽  
Great Success ◽  
Free Space Optical

AbstractSince the great success of optical communications utilizing orbital angular momentum (OAM), increasing the number of addressable spatial modes in the given physical resources has always been an important yet challenging problem. The recent improvement in measurement resolution through deep-learning techniques has demonstrated the possibility of high-capacity free-space optical communications based on fractional OAM modes. However, due to a tiny gap between adjacent modes, such systems are highly susceptible to external perturbations such as atmospheric turbulence (AT). Here, we propose an AT adaptive neural network (ATANN) and study high-resolution recognition of fractional OAM modes in the presence of turbulence. We perform simulations of fractional OAM beams propagating through a 1-km optical turbulence channel and analyze the effects of turbulence strength, OAM mode interval, and signal noise on the recognition performance of the ATANN. The recognition of multiplexed fractional modes is also investigated to demonstrate the feasibility of high-dimensional data transmission in the proposed deep-learning-based system. Our results show that the proposed model can predict transmitted modes with high accuracy and high resolution despite the collapse of structured fields due to AT and provide stable performance over a wide SNR range.

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.

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