This book introduces in detail the theory of adaptive optics and its correction technology for light wave distortion in wireless optical communication. It discusses the adaptive control algorithm of wavefront distortion, proportional+integral control algorithm and iterative control algorithm, and double fuzzy adaptive PID control algorithm. It also covers the SPGD algorithm of adaptive optics correction, deformable mirrors eigenmode method of wavefront aberration correction, vortex beam wavefront detecting wavefront aberration correction, liquid crystal spatial light modulator wavefront correction, different wavelengths of Gaussian beam transmission wavefront differences in the atmospheric turbulence and correction and with wavefront tilt correction adaptive optics wavefront aberration correction. Various distortion correction methods are verified by experiments and the experimental results are analyzed.
This book is suitable for engineering and technical personnel engaged in wireless optical communication, college teachers, graduate students and senior undergraduate students.
Author(s): Xizheng Ke, Pengfei Wu
Series: Optical Wireless Communication Theory and Technology, 237
Publisher: Springer
Year: 2022
Language: English
Pages: 386
City: Singapore
Preface
Introduction
Contents
1 Introduction
1.1 Wireless Optical Coherent Communication Research Status
1.1.1 Research Status in the United States
1.1.2 Research Status in Europe
1.1.3 Research Status of Japan
1.1.4 Research Status of China
1.2 Adaptive Optics
1.2.1 International Research Progress in Adaptive Optics
1.2.2 Chinese Research Progress in Adaptive Optics
1.2.3 Adaptive Optics Development Trends
References
2 Coherent Optical Communication
2.1 Basic Principles of Coherent Optical Communication
2.1.1 Fundamentals
2.1.2 Homodyne Detection
2.1.3 Heterodyne Detection
2.1.4 Detection of an Amplitude Modulated Signal
2.1.5 Dual-Channel Balanced Detection
2.2 Coherent Modulation and Demodulation
2.2.1 Optical Modulation
2.2.2 Coherent Demodulation
2.2.3 System Performance
2.3 Factors Affecting Detection Sensitivity
2.3.1 Phase Noise
2.3.2 Intensity Noise
2.3.3 Polarization Noise
2.3.4 Key Technologies of Coherent Optical Communication Systems
2.4 Spatial Phase Conditions for Optical Heterodyne Detection
2.4.1 Spatial Phase Difference Conditions
2.4.2 Frequency Conditions
2.4.3 Polarization Conditions
2.5 Summary and Outlook
References
3 Adaptive Control of Wavefront Distortion
3.1 The Basic Principle of Coherent Optical Communication
3.2 Adaptive Optics Technology
3.2.1 Basic Principles
3.2.2 Wavefront Sensor
3.2.3 Wavefront Corrector
3.2.4 Wavefront Distortion Correction Principle
3.2.5 Beam Quality Evaluation Index
3.3 Wavefront Correction Algorithm of a Double Deformable Mirror
3.3.1 Wavefront Distortion Caused by Atmospheric Turbulence
3.3.2 Numerical Analysis of Wavefront Distortion
3.3.3 Experiment on Adaptive Control of Wavefront Distortion of Pendulum Mirror and Deformable Mirror
3.4 Wavefront Distortion Predictive Control
3.4.1 Adaptive Optics Model
3.4.2 Subspace System Identification
3.4.3 Predictive Control Experiment of Wavefront Distortion
3.5 System Error Analysis and Suppression
3.5.1 Error Analysis of Adaptive Optics System
3.5.2 Method of Restraining System Error
3.5.3 Comparison of Error Suppression Methods
3.6 Adaptive Control of Wavefront Distortion
3.6.1 PI Control Algorithm
3.6.2 Closed-Loop Control Parameter Adjustment
3.7 System Calibration
3.7.1 System Composition
3.7.2 Push–Pull Calibration
3.7.3 Hadamard Matrix Calibration
3.8 Closed-Loop
3.8.1 Closed-Loop Algorithm
3.8.2 Closed-Loop Bandwidth
References
4 Adaptive Optics Calibration Methods
4.1 Proportional Integral Algorithm
4.1.1 System Response Matrix Calibration
4.1.2 Control Principles of PI Algorithm based on Direct Slope Method
4.1.3 Control Principles of Iterative Algorithm
4.2 Influence of Parameters on PI and Iterative Algorithms
4.2.1 PI Control Algorithm Parameters
4.2.2 G–S Algorithm Parameters
4.2.3 ILC Algorithm Parameters
4.2.4 Comparing the PI and Iterative Algorithms
4.2.5 Algorithm Operation Volume Analysis
4.3 Coherent Optical Communication Wave Front Correction Experiment
4.3.1 Analysis of the Closed-Loop Control Effect of the Wave Front Controller
4.3.2 Influence of AO Closed Loop Correction on Wave Front PV and Wave Front Root Mean Square
4.3.3 Influence of AO Closed-Loop Correction on Coupling Effect and Intermediate Frequency Signal
References
5 Dual Fuzzy Adaptive Proportional Integral Derivative (PID) Control
5.1 Dual Fuzzy Adaptive PID Control Principle Based on the Direct Slope Method
5.2 Influence of the Input and Output Domains on the Fuzzy Adaptive PID Algorithm
5.2.1 Control Voltage
5.2.2 First Derivative of the Control Voltage
5.2.3 Output Domain
5.3 Fuzzy Control Experiment
5.3.1 Experimental Setup of the AO System
5.3.2 Iterative Control Algorithm Calibration Experiment
5.3.3 PID Control Algorithm Calibration Experiment
References
6 Wave Front Correction Using the Stochastic Parallel Gradient Descent (SPGD) Algorithm
6.1 Wave Front Correction of Distorted Gaussian Beams Using the SPGD Algorithm
6.1.1 SPGD Algorithm
6.1.2 Optical Transmission Equation and Multiphase Screen Method
6.1.3 Simulation of Gaussian Beam Propagation in Atmospheric Turbulence
6.1.4 Wave Front Correction under Different Turbulence Intensities
6.1.5 Performance Improvement of Coherent Optical Communication System Using AO
6.2 Wave Front Distortion Correction Experiment Using the SPGD Algorithm
6.2.1 Correction of Static Wave Front Distortion
6.2.2 Wave Front Correction of a Heterodyne Detection Coherent Optical Communication System Using the SPGD Algorithm
References
7 Wave Front Distortion Correction Using Deformable Mirror Eigenmode Method
7.1 Deformable Mirror Method
7.1.1 System Functions
7.1.2 Correction Factor
7.1.3 Deformable Mirror Intrinsic Mode
7.2 Simulating Wave Front Correction Using the Eigenmode Method
7.2.1 Calibration Process and Method
7.2.2 Deformable Mirror Modeling and Its Eigenmode
7.3 Wave Front Correction Simulation Using the Deformable Mirror Eigenmode Method
7.3.1 Influence of Turbulence Intensity
7.3.2 Fast Stable Convergence
7.3.3 Comparison of Different Correction Algorithms
7.4 Deformable Mirror Eigenmode Method
7.4.1 The Deformable Mirror Influence Function and Its Eigenmode
7.4.2 Static Aberration Correction Experiment
7.4.3 Field Experiment
References
8 Vortex Beam Wave Front Correction Without Using a Wave Front Detector
8.1 Vortex Beam Propagation Characteristics Through Atmospheric Turbulence
8.1.1 Laguerre-Gaussian (LG) Beam
8.1.2 Vortex Beam Transmission Through Atmospheric Turbulence
8.1.3 Orbital Angular Momentum (OAM) of the Vortex Beam
8.2 Wave Front Correction Using the Phase Difference Method
8.2.1 Principles of Wave Front Correction Using the Phase Difference Method
8.2.2 Numerical Simulation of Vortex Beam Correction Using the Phase Difference Method
8.2.3 Convergence Analysis of the Phase Distribution Algorithm
8.3 Vortex Beam Correction Using the Gerchberg–Saxton (GS) Algorithm
8.3.1 Correction Principle
8.3.2 Simulation Results
8.4 Stochastic Parallel Gradient Descent (SPGD) Algorithm
8.5 Wave Front Distortion Correction Experiment Using the GS and SPGD Algorithms
8.5.1 GS Algorithm
8.5.2 SPGD Algorithm
References
9 Liquid Crystal Adaptive Optics
9.1 Principles of Liquid Crystal Phase Modulation
9.1.1 Structure of a liquid crystal spatial light modulator (LC-SLM)
9.1.2 Principles of am LC-SLM
9.1.3 Wave Front Distortion Control Method
9.2 Phase Calibration Principles of LC-SLM
9.2.1 Interference Fringe Movement Method
9.2.2 Experimental Principle of the Interference Fringe Movement Method
9.3 Phase Calibration Experiment
9.3.1 Reflective LC-SLM Phase Calibration Experiment
9.3.2 Least Squares Fitting
9.4 Reflective LC-SLM Spatial Coherent Optical Communication Wave Front Correction System
9.4.1 Wave Front Correction Principle Using a Reflective LC-SLM
9.4.2 Basic Composition of the Wave Front Correction System
9.5 Principles of Wave Front Measurement
9.5.1 Static Wave Front Measurement Using the Transverse Shear Interferometer
9.5.2 Shack–Hartmann Real-Time Wave Front Measurement Principle
9.6 Wave Front Reconstruction
9.6.1 Zernike Polynomial
9.6.2 Wave Front Reconstruction Using the Zernike Polynomial
9.7 Reflective LC-SLM Wave Front Correction Experiment
9.7.1 Static Wave Front Correction
9.7.2 Field Experiment
References
10 Wave Front Variations of Gaussian Beams with Different Wavelengths Propagating in Atmospheric Turbulence
10.1 Beam Propagation in Turbulence
10.1.1 Wave Front Fluctuation Variance Corresponding to Different Wavelengths
10.1.2 Wave Front Fluctuation of Different Wavelength Beams
10.2 Dual Wavelength Adaptive Optics
10.2.1 Adaptive Optics (AO)
10.2.2 Influence of the Wave Front Sensor on Detection Performance
10.3 Influence of the Wave Front Corrector
10.3.1 Impact of System Bandwidth
10.3.2 Wave Front Correction Coefficient Corresponding to Wavelength
10.4 Numerical Simulation and Analysis
10.4.1 Numerical Simulation of Global Wave Front Variance
10.4.2 Wave Front Correlation
10.4.3 Wave Front Spatial Differences on the Receiving Aperture
10.4.4 Correction Status with Correction Factor
10.4.5 Wave Front Distortion Experiment Corresponding to Different Wavelengths
References
11 Adaptive Control of Large Amplitude Wave Front Distortion and Tilt
11.1 Residual Correction of Large Amplitude Wave Front Distortion
11.1.1 Theoretical Analysis of Large Amplitude Wave Front Distortion
11.1.2 Simulation analysis of large amplitude wave front distortion
11.1.3 Experimental Study
11.2 Adaptive Optical Wave Front Distortion Correction Using Wave Front Tilt Correction
11.2.1 Theoretical wave Front Distortion in Atmospheric Turbulence
11.2.2 Wave Front Distortion Experiment in Atmospheric Turbulence
References
