scholarly journals Topological Charge and Asymptotic Phase Invariants of Vortex Laser Beams

Photonics ◽  
2021 ◽  
Vol 8 (10) ◽  
pp. 445
Author(s):  
Alexey A. Kovalev ◽  
Victor V. Kotlyar ◽  
Anton G. Nalimov
Keyword(s):  
Numerical Simulation ◽  
Data Transmission ◽  
Topological Charge ◽  
Light Field ◽  
Observation Point ◽  
Laser Beams ◽  
Optical Data ◽  
Optical Signals ◽  
Asymptotic Phase ◽  
Ring Approximation

It is well known that the orbital angular momentum (OAM) of a light field is conserved on propagation. In this work, in contrast to the OAM, we analytically study conservation of the topological charge (TC), which is often confused with OAM, but has quite different physical meaning. To this end, we propose a huge-ring approximation of the Huygens–Fresnel principle, when the observation point is located on an infinite-radius ring. Based on this approximation, our proof of TC conservation reveals that there exist other quantities that are also propagation-invariant, and the number of these invariants is theoretically infinite. Numerical simulation confirms the conservation of two such invariants for two light fields. The results of this work can find applications in optical data transmission to identify optical signals.

scholarly journals Optical beams with an infinite number of vortices

2021 ◽  
Vol 45 (4) ◽  
pp. 490-496
Author(s):  
V.V. Kotlyar
Keyword(s):  
Angular Momentum ◽  
Cross Section ◽  
Data Transmission ◽  
Topological Charge ◽  
Laser Beams ◽  
Optical Data ◽  
Optical Vortices ◽  
Straight Line ◽  
Phase Singularities ◽  
Light Beams

In optical data transmission with using vortex laser beams, data can be encoded by the topo-logical charge, which is theoretically unlimited. However, the topological charge of a single sepa-rate vortex is limited by possibilities of its generating. Therefore, in this work, we analyze light beams with an unbounded (countable) set of optical vortices. The summary topological charge of such beams is infinite. Phase singularities (isolated intensity nulls) in such beams typically have a unit topological charge and reside equidistantly (or not equidistantly) on a straight line in the beam cross section. Such beams are form-invariant and, on propagation in space, change only in scale and rotate. Orbital angular momentum of such multivortex beams is finite, since only a finite number of optical vortices fall into the area, where the Gaussian beam has a notable intensity. Other phase singularities are located in the periphery (and at the infinity), where the intensity is almost zero.

scholarly journals Topological charge of optical vortices devoid of radial symmetry

2020 ◽  
Vol 44 (4) ◽  
pp. 510-518
Author(s):  
A.A. Kovalev
Keyword(s):  
Numerical Simulation ◽  
Topological Charge ◽  
Radial Symmetry ◽  
Laser Beams ◽  
Beam Power ◽  
Optical Vortices ◽  
Phase Retardation ◽  
Beam Asymmetry ◽  
Angular Momenta ◽  
Theoretical Predictions

Here we theoretically obtain values of the topological charge (TC) for vortex laser beams devoid of radial symmetry: asymmetric Laguerre-Gaussian (LG) beams, Bessel-Gaussian (BG) beams, Kummer beams, and vortex Hermite-Gaussian (HG) beams. All these beams consist of conventional modes, namely, LG, BG, or HG modes, respectively. However, all these modes have the same TC equal to that of a single constituent mode n. Orbital angular momenta (OAM) of all these beams, normalized to the beam power, are different and changing differently with varying beam asymmetry. However, for arbitrary beam asymmetry, TC remains unchanged and equals n. Superposition of just two HG modes with the adjacent numbers (n, n+1) and with the phase retardation of (pi)/2 yields a modal beam with the TC equal to – (2n+1). Numerical simulation confirms the theoretical predictions.

Analog ghost hidden in 2D random binary patterns for free-space optical data transmission

2022 ◽  
Vol 150 ◽  
pp. 106880
Author(s):  
Yin Xiao ◽  
Lina Zhou ◽  
Zilan Pan ◽  
Yonggui Cao ◽  
Mo Yang ◽  
...  
Keyword(s):  
Data Transmission ◽  
Free Space ◽  
Optical Data ◽  
Free Space Optical

DML and ILO based clock recovery scheme for burst-mode 4-PAM optical data transmission in PON

Optik ◽  
2013 ◽  
Vol 124 (14) ◽  
pp. 1696-1699
Author(s):  
Minhui Yan ◽  
Weifeng Shi
Keyword(s):  
Data Transmission ◽  
Clock Recovery ◽  
Optical Data ◽  
Burst Mode ◽  
Recovery Scheme

High-Speed Semiconductor Vertical-Cavity Surface-Emitting Lasers for Optical Data-Transmission Systems (Review)

2018 ◽  
Vol 44 (1) ◽  
pp. 1-16 ◽  
Author(s):  
S. A. Blokhin ◽  
N. A. Maleev ◽  
M. A. Bobrov ◽  
A. G. Kuzmenkov ◽  
A. V. Sakharov ◽  
...  
Keyword(s):  
Data Transmission ◽  
High Speed ◽  
Optical Data ◽  
Cavity Surface ◽  
Transmission Systems ◽  
Surface Emitting Lasers ◽  
Vertical Cavity Surface ◽  
Emitting Lasers ◽  
Vertical Cavity

Optical Data Link Module for Data Transmission in Smart Catheters

2020 ◽  
Vol 2020 (1) ◽  
pp. 000169-000173
Author(s):  
Jian Li ◽  
Vincent Henneken ◽  
Marcus Louwerse ◽  
Ronald Dekker
Keyword(s):  
Data Transmission ◽  
System Integration ◽  
Electrical Contacts ◽  
Optical Data ◽  
Cavity Surface ◽  
Data Link ◽  
Technology Platform ◽  
Limited Space ◽  
Vertical Cavity Surface ◽  
Link Module

Abstract We demonstrate a stand-alone optical data link module (ODLM) that fits in the limited space budget of smart imaging catheters. The module is based on an extension of the Flex-to-Rigid (F2R) technology platform for miniaturized system integration. The ODLM is a silicon-based interposer that comprises a commercially available Vertical Cavity Surface Emitting Laser (VCSEL), which has its electrical contacts and laser emitting spot on the same surface. With the flexible interconnects, the ODLM reroutes the flip-chipped VCSEL electrical contacts to the side that is perpendicular to the surface of the VCSEL. This enables the ODLM to be mounted on a flex-PCB and fit into the limited space in the distal tip of the smart catheter. An optical fiber that runs in parallel to the catheter shaft is inserted into the through-silicon hole (TSH) of the ODLM and self-aligned to the VCSEL for optical data transmission. The design of the ODLM and the F2R technology platform are introduced, and an ODLM demonstrator is fabricated and presented.

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