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Coherent OAM (Orbital Angular Momentum) communication demodulation system based on convolutional neural network

A convolutional neural network and communication demodulation technology, applied in biological neural network models, transmission systems, neural architectures, etc., can solve problems such as increased costs, complex coherent detection and demodulation, and achieve improved utilization and low-cost accurate solutions Tuning and operation are simple

Inactive Publication Date: 2019-03-08
TONGJI UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

This technology no longer uses simple intensity detection, but uses more complex coherent detection and demodulation, which increases the cost

Method used

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  • Coherent OAM (Orbital Angular Momentum) communication demodulation system based on convolutional neural network
  • Coherent OAM (Orbital Angular Momentum) communication demodulation system based on convolutional neural network
  • Coherent OAM (Orbital Angular Momentum) communication demodulation system based on convolutional neural network

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Experimental program
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Embodiment 1

[0028] like figure 1 As shown, a coherent OAM communication demodulation system based on convolutional neural network, including:

[0029] The light source generating device includes a laser, a spiral phase plate (SPP) and a lens. The beam generated by the laser first passes through the spiral phase plate to generate an optical vortex with OAM, and then passes through the lens to generate a Laguerre-Gauss (Laguerre-Gaussian) carrying OAM. -Gaussia, LG) light beam; OAM coherent modulation device, including an optical modulator (modulator such as Mach-Zehnder interferometer), connected to the light source generator, and using coherent modulation to generate multiple OAM coherent modulation signals; OAM coherent modulation signal beam combining device, Contains spatial optical coupling devices, such as holographic optical elements, spatial gratings, spatial light modulators (spatial light modulator, SLM), etc., connected to OAM coherent modulation devices, and couples the generat...

Embodiment 2

[0042] In this embodiment, data different from that in Embodiment 1 is generated, a light source generating device is used to generate an LG light beam carrying OAM, two different OAM modes are selected, m=[-1,2], and a QPSK signal is modulated. The establishment of the convolutional neural network adopts the same method as that of Embodiment 1, and the OAM coherent modulation signal in the form of light intensity distribution is divided into 4 categories according to the modulation information, wherein the topological charge of the LG beam m=-1 corresponds to the OAM mode modulation 0 phase Information, OAM mode modulation corresponding to m=2 The phase information of four states, so two OAM modes can carry four kinds of modulation information in total, and the set of all LG beams carrying different modulation information is called a matrix set. Then label the LG beams 0, 1, 2, and 3 according to different modulation information. Each type of label represents a modulation in...

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Abstract

The invention relates to a coherent OAM (Orbital Angular Momentum) communication demodulation system based on a convolutional neural network. The system comprises a light source generation device which generates an LG light beam carrying an OAM; an OAM coherent modulation device which generates multiway OAM coherent modulation signals through coherent modulation; an OAM coherent modulation signalcombination device which couples the multiway generated OAM coherent modulation signals into one way for transmission; a receiving processing device which receives the multiway OAM coherent modulationsignals and converts the signals into the signals of a light intensity distribution form; and a CNN demodulation device which is connected with the receiving processing device and classifies and identifies the OAM coherent modulation signals of the light intensity distribution form through utilization of the convolutional neural network, thereby obtaining multiway demodulated OAM coherent modulation signals. Compared with the prior art, the system has the advantages that a coherent light communication technology is combined with machine learning, demodulation convenience of a coherent OAM communication system is improved, a utilization rate of OAM optical carriers is improved, operation is simple, and cost is relatively low.

Description

technical field [0001] The invention relates to a demodulation system of an OAM coherent modulation signal, in particular to a coherent OAM communication demodulation system based on a convolutional neural network. Background technique [0002] Digital OAM (Quadrature Amplitude Modulation) modulation technology is widely used in broadcast communication fields such as digital TV because of its high spectrum utilization rate and strong anti-interference ability. Document 1 "Turbulence-induced channel crosstalk in an orbital angular momentum-multiplexed free-space optical link" (Anguita J A, Neifeld M A, Vasic B V.[J].Appl Opt,2008,47(13):2414-2429.) It is proposed that in Free Space Optical Communication (FSO) without atmospheric disturbance, the LG beam carrying OAM can be expressed as: [0003] [0004] [0005] [0006] Among them, z is the transmission distance of the LG beam; r is the radial distance from the LG beam to the transmission axis; is the normalized...

Claims

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Application Information

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IPC IPC(8): H04B10/516H04B10/548G06N3/04
CPCH04B10/516H04B10/548G06N3/045
Inventor 周俊鹤胡静樊盼盼吴建杰
Owner TONGJI UNIV