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Application of the stochastic parallel gradient descent algorithm for numerical simulation and analysis of the coherent summation of radiation from fibre amplifiers

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QUANTUM ELECTRONICS 2009年第10期39卷 981-984页

作者： Zhou, Pu Wang, Xiaolin Li, Xiao Chen, Zilun Xu, Xiaojun Liu, Zejin Natl Univ Def Technol Coll Optoelect Sci & Engn Changsha 410073 Hunan Peoples R China

Coherent summation of fibre laser beams, which can be scaled to a relatively large number of elements, is simulated by using the stochastic parallel gradient descent (SPGD) algorithm. The applicability of this algorit... 详细信息

关键词： coherent summation fibre laser stochastic parallel gradient descent algorithm

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Performance investigation of stochastic parallel gradient descent algorithm based wave-front sensor-less adaptive optics for atmosphere turbulence compensation 4

Performance investigation of stochastic parallel gradient de...

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4th Seminar on Novel Optoelectronic Detection Technology and Application

作者： Yu, Zhihao Li, Yan Li, Beibei Zheng, Donghao Li, Wei Qiu, Jifang Zuo, Yong Hong, Xiaobin Guo, Hongxiang Wu, Jian Beijing Univ Posts & Telecommun State Key Lab Informat Photon & Opt Commun Beijing 100876 Peoples R China

ISBN: (数字)9781510619487

ISBN: (纸本)9781510619487

stochastic parallel gradient descent (SPGD) algorithm is a kind of simple and practicable algorithm for adaptive optics (AO) to compensate the effects of turbulence. The relationship between the number of control variables and convergence effects is explored experimentally in this paper. We find that the number of control variables is not always the larger the better. Under the condition of weak turbulence, the algorithm with 6x6 control variables gives better results than 12x12 control variables and 8x8 control variables. With the increase of turbulence strength, the convergence effects of 12x12 control variables are better than 6x6 control variables and 8x8 control variables. In the condition of weak turbulence, SPGD algorithm with 6x6, 8x8, 12x12 control variables can improve coupling efficiency by 3.2dB, 3.1dB and 3.0dB respectively. In the condition of moderate turbulence, SPGD algorithm with 6x6, 8x8, 12x12 control variables can improve coupling efficiency by 6.4dB, 6.6dB, 7.1dB respectively. In the condition of strong turbulence, SPGD algorithm with 6x6, 8x8, 12x12 control variables can improve coupling efficiency by 6.2dB, 7.1dB, 10.2dB respectively.

关键词： free space optics communication adaptive optics stochastic parallel gradient descent algorithm

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Laser beam shaping based on wavefront sensorless adaptive optics with stochastic parallel gradient descent algorithm 14

Laser beam shaping based on wavefront sensorless adaptive op...

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14th National Conference on Laser Technology and Optoelectronics (LTO)

作者： Li, Yan Peng, Tairan Li, Wenlai Han, Hongming Ma, Jianqiang Ningbo Univ Fac Mech Engn & Mech Ningbo 315211 Zhejiang Peoples R China

ISBN: (数字)9781510630475

ISBN: (纸本)9781510630475

A wavefront sensorless adaptive optics system with a 61-element unimorph deformable mirror is proposed for laser beam shaping. The actuator voltages of the DM are adaptively adjusted with the help of the stochastic parallel gradient descent (SPGD) algorithm. The difference of the target beam and the actual beam recorded by a CCD camera is used as feedback. The experimental results show that this method not only realizes the aberrations correction of the optical system, but also generates annular beam, ratio line focus beam and square beam which agree with the desired targets.

关键词： beam shaping adaptive optics deformable mirror stochastic parallel gradient descent algorithm

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Adaptive conversion of a wavefront-distortion beam to near-diffraction-limited flattop beam based on stochastic parallel gradient descent algorithm

Adaptive conversion of a wavefront-distortion beam to near-d...

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Conference on High-Power Lasers and Applications V

作者： Ma Haotong Yu Zhan Wang Xiaolin Ma Yanxing Zhou Pu Xu Xiaojun Liu Zejin Natl Univ Def Technol Coll Photon Electron Sci & Engn Changsha 410073 Hunan Peoples R China

ISBN: (纸本)9780819483737

In this paper, a system of containing dual deformable mirrors (DMs) is proposed to adaptively conversion of input beam with wave front distortion into near-diffraction-limited flattop beam based on the stochastic parallel gradient descent (SPGD) algorithm. In the analysis, the wave front distortion of the input beam is chosen as the Zernike representation of Kolmogoroff spectrum of turbulence. The whole shaping system is controlled by the SPGD algorithm. One DM adaptively redistributes the intensity of the input beam and the other adaptively compensates the wave front of the output beam. The near-diffraction-limited flattop beams with different parameters are realized by this technique. The near-diffraction-limited square flattop beam retains an flattop intensity distribution without significant diffraction peaks for a working distance of more than 60cm in the near field.

关键词： near field laser beam shaping deformable mirror near-diffraction-limited stochastic parallel gradient descent algorithm

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Coherent combining of multi-wavelength fiber amplifiers using a stochastic parallel gradient descent algorithm

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JOURNAL OF OPTICS 2010年第7期12卷 075701-075701页

作者： Wang, Xiaolin Zhou, Pu Ma, Yanxing Ma, Haotong Xu, Xiaojun Liu, Zejin Zhao, Yijun Natl Univ Def Technol Coll Optoelect Sci & Engn Changsha 410073 Hunan Peoples R China

Multi-wavelength and non-single-frequency seed lasers can be used to suppress stimulated Brillouin scattering and improve the ultimate output power of a fiber laser amplifier. Coherent combining of non-single-frequency and/or multi-wavelength lasers/amplifiers is a promising way to obtain much higher total output power than from coherent combining of single-frequency lasers/amplifiers. Using a stochastic parallel gradient descent algorithm, we demonstrate coherent combining of four-channel multi-wavelength lasers in a master oscillator power amplifier (MOPA) configuration. Four lasers with different wavelengths, namely two non-single-frequency and two single-frequency lasers, are used. The mean power of the main lobe in the closed-loop case is three times that for the open-loop case, approaching 75% of its ideal value. The coherent combining of multi-wavelength and non-single-frequency lasers in a MOPA configuration is validated, and a feasible approach for scaling to high power coherent combining is provided.

关键词： fiber laser coherent combining multi-wavelength non-single frequency stochastic parallel gradient descent algorithm

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Numerical and experimental study on coherent beam combining using an improved stochastic parallel gradient descent algorithm

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LASER PHYSICS 2020年第8期30卷

作者： Song, Jikun Li, Yuanyang Che, Dongbo Wang, Tingfeng Chinese Acad Sci Changchun Inst Opt Fine Mech & Phys State Key Lab Laser Interact Matter Changchun 130033 Peoples R China Univ Chinese Acad Sci Ctr Mat Sci & Optoelect Engn Beijing 100049 Peoples R China

The adaptive gradient (AdaGrad) method is an optimization algorithm widely used in the field of artificial intelligence. An adaptive gradient stochastic parallel gradient descent (SPGD) algorithm (AdaSPGD algorithm), combining an AdaGrad algorithm with an SPGD algorithm, is innovatively introduced and implemented in coherent beam synthesis. The performance of a coherent beam combination system utilizing the AdaSPGD method is validated by numerical simulation of straightening static phase aberrations. The results of the simulations indicate that the AdaSPGD algorithm not only can effectively solve the trouble of difficulty in selecting the gain coefficient in the actual beam combining system, but also can accelerate the convergence of the phase control algorithm. Furthermore, the effectiveness of the proposed algorithm is demonstrated by means of the experimental investigation on coherent beam synthesis of a two-channel fiber array. The AdaSPGD algorithm is a satisfactory modification of the conventional SPGD algorithm.

关键词： coherent beam combining adaptive gradient stochastic parallel gradient descent algorithm

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Tip-tilt adaptive correction based on stochastic parallel gradient descent optimization algorithm

Tip-tilt adaptive correction based on stochastic parallel gr...

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Conference on Optical Design and Testing IV

作者： Ma, Huimin Zhang, Pengfei Zhang, Jinghui Qiao, Chunhong Fan, Chengyu Chinese Acad Sci Anhui Inst Opt & Fine Mech Key Lab Atmospher Composit & Opt Radiat Hefei 230031 Anhui Peoples R China

ISBN: (纸本)9780819483799

Adaptive optics correcting technique based on stochastic parallel gradient descent (SPGD) control algorithm is an alternative approach which is independent of wavefront sensor and optimizes the performance metric directly. In this paper we establish a simulation model of tip-tilt adaptive optics system, where SPGD optimization algorithm is used to correct the tip-tilt aberration induced by dynamic turbulence. The distance between the measured centroid of a blurring image and the demarcated centroid of the ideal image is considered as the system performance metric, and signals applied to compensation of the drifting atmosphere are generated for tip-tilt mirror. The sensitivity of the performance metrics is investigated, and the convergence rate and the stability are analyzed. By means of this optimization algorithm, the centroid of the image is modified in real time, which results in the improvement of the long exposure image.

关键词： adaptive optics stochastic parallel gradient descent algorithm tip-tilt numerical simulation

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Tip-tilt adaptive correction based on stochastic parallel gradient descent optimization algorithm

Tip-tilt adaptive correction based on stochastic parallel gr...

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2010亚洲光电子会议光学设计和检验分会场

作者： Huimin Ma *,Pengfei Zhang,Jinghui Zhang,Chunhong Qiao,Chengyu Fan Key Laboratory of Atmospheric Composition and Optical Radiation,Anhui Institute of Optics and Fine Mechanics,Chinese Academy of Sciences,P.O.Box1125,Hefei,Anhui 230031,China

Adaptive optics correcting technique based on stochastic parallel gradient descent(SPGD) control algorithm is an alternative approach which is independent of wavefront sensor and optimizes the performance metric *** this paper we establish a simulation model of tip-tilt adaptive optics system,where SPGD optimization algorithm is used to correct the tip-tilt aberration induced by dynamic *** distance between the measured centroid of a blurring image and the demarcated centroid of the ideal image is considered as the system performance metric,and signals applied to compensation of the drifting atmosphere are generated for tip-tilt *** sensitivity of the performance metrics is investigated,and the convergence rate and the stability are *** means of this optimization algorithm,the centroid of the image is modified in real time,which results in the improvement of the long exposure image.

关键词： adaptive optics stochastic parallel gradient descent algorithm tip-tilt numerical simulation

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Wave-front Correction with a Multilevel stochastic parallel gradient descent Technique

Wave-front Correction with a Multilevel Stochastic Parallel ...

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8th Pacific Rim Conference on Lasers and Electro-Optics

作者： Wang, Sanhong Yu, Qifeng Liang, Yonghui Natl Univ Def Technol Coll Optoelect Sci & Engn Changsha 410073 Hunan Peoples R China

An adaptive optics (AO) system composed of multiple control levels based on the stochastic parallel gradient descent (SPGD) technique is discussed Results of numerical simulations demonstrate that the convergence rate... 详细信息

ISBN: (纸本)9781424438297

关键词： Adaptive optics stochastic parallel gradient descent algorithm multilevel wave-front correction effective correction bandwidth

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SPGD and Newton iteration mixed algorithm used in freeform surface metrology

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OPTICS AND LASERS IN ENGINEERING 2020年 129卷 106050-106050页

作者： Zhang, Yu Tian, Xiaobo Liang, Rongguang Northeast Elect Power Univ Coll Sci Inst Mat Phys Jilin 132012 Jilin Peoples R China Chinese Acad Sci Changchun Inst Opt Fine Mech & Phys State Key Lab Appl Opt Changchun 130022 Jilin Peoples R China Univ Arizona Coll Opt Sci Tucson AZ 85721 USA

Freeform surfaces are widely used in advanced optical systems. In order to accurately measure freeform surfaces, an adaptive interferometer with deformable mirror (DM) has been developed for the freeform surface metrology. To ensure the efficiency, a stochastic parallel gradient descent (SPGD) and Newton iteration mixed algorithm to drive the DM has been proposed, it can achieve the minimum value of the optimization and is suitable for the different interferograms. The simulation and experimental results verify the correctness and feasibility of the proposed DM driving algorithm.

关键词： stochastic parallel gradient descent algorithm Newton iteration algorithm Deformable mirror Freeform surface Optimization

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