Self-focusing vortex beam generation method for suppressing turbulence effect

Abstract

The invention discloses a novel self-focusing vortex beam generating method for suppressing turbulence effect. It mainly solves the problems of beam expansion and wavefront phase distortion caused by the vortex beam propagating in the turbulent medium. The scheme is: 1) according to the channel environment, detect the channel signal-to-noise ratio γ; 2) compare the current channel signal-to-noise ratio γ with the threshold value η: if γ≥η, then perform 3), otherwise, perform 4); 3) Generate a sustainable self-focusing needle-shaped single vortex beam; 4) Generate an array-type needle-shaped vortex beam with high power and adjustable focus position; 5) Use a spatial filter to load the obtained vortex beam with a filter factor , to filter out the aliasing modes in the beam, and obtain the new self-focusing vortex beam required by the system. The present invention considers the transmitting end of the system, selects the new self-focusing vortex beam required by the system according to the channel environment under different conditions, improves the effectiveness and reliability of the orbital angular momentum FSO communication system, and can be used for communication with turbulent flow as the medium system.

Description

technical field [0001] The invention belongs to the technical field of communication, and in particular relates to a method for generating a self-focusing vortex beam, which can be used to generate a vortex beam for improving FSO communication performance at a transmitting end in a communication system using turbulence as a medium. Background technique [0002] In recent years, with the continuous deepening of informatization, the rapid development of mobile communication services and Internet technology has greatly increased the demand for communication effectiveness and reliability. At present, the multiplexing methods commonly used in the communication field include: time division, space division, frequency division and code division multiplexing. Although these technical methods can alleviate the contradiction between channel capacity and user demand, with the further development of user demand for information bandwidth and data rate, a new technology that can further im...

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Problems solved by technology

However, these two methods do not consider how to control the focus position of the array beam and filter out the aliasing mode, which leads to the inability to obtain the best received signal at the receiving end of the system when determining a transmission distance, thus failing to further improve the system effectiveness and reliability

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