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Highly sensitive fiber coupling for free-space optical communications based on an adaptive coherent fiber coupler

OPTICS COMMUNICATIONS 2019年 430卷 223-226页

作者： Chen, Mo Liu, Chao Rui, Daoman Xian, Hao Chinese Acad Sci Key Lab Adapt Opt Chengdu 610209 Sichuan Peoples R China Chinese Acad Sci Inst Opt & Elect Chengdu 610209 Sichuan Peoples R China Univ Chinese Acad Sci Beijing 100049 Peoples R China

In this paper, we present the result that the performances of the highly sensitive adaptive coherent fiber coupling (ACFC) technology, which consists of a movable fiber tip and a coherent detector. The ACFC technology is applied for the free-space coherent optical communication systems especially with a long distance link such as the satellite to ground, and it is used for compensating the tiny random angular jitter caused by the vibration of the receiver and the residual jitter error of the adaptive optics unit which is used for alleviating the effect of turbulence. Compared with the traditional fiber coupling using direct detection, the advantages of ACFC technology has been verified by analyzing the SNR value. The result shows that the receiver sensitivity can be enhanced by up to 20 dB. The residual jitter error of a free-space optical receiver with a 357-element AO unit is acquainted, and it is used for verifying the performance of the ACFC technology. The result shows that the average coupling efficiency is 73.2% with a mean square error (MSE) 1.12%, increasing significantly compared with the average coupling efficiency 50.1% and a MSE 7.43% without ACFC correction.

关键词： Adaptive optics Coherent fiber coupling Free-space optical communication spgd algorithm

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A dark-hole correction test for the step-transmission filter based coronagraph system

A dark-hole correction test for the step-transmission filter...

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Conference on Space Telescopes and Instrumentation - Optical, Infrared, and Millimeter Wave

作者： Dou, Jiangpei Ren, Deqing Zhu, Yongtian Zhang, Xi Li, Rong Chinese Acad Sci Nanjing Inst Astron Opt & Technol Natl Astron Observ Nanjing 210042 Jiangsu Peoples R China

ISBN: (纸本)9780819491435

We present the initial test of the dark-hole correction for the high-contrast imaging coronagraph that is based on the step-transmission filter. The dark hole is created by a 12x12 actuator deformable mirror (DM) that has been put in the conjugate plane of the pupil image of the coronagraph. In this test, we use the stochastic parallel gradient descent (spgd) optimization algorithm to directly control the DM to provide an optimal phase to minimize the intensity in target regions, where the dark hole is created and the contrast can be enhanced. For demonstration purpose, the test is carried out in a single wavelength and should be improved in next step for broad-band high-contrast imaging. Finally, it is shown in the test that an extra contrast similar to 50 times improvement has reached in the dark hole in the coronagraphic image plane. Such a technique could be used for a future space-based high-contrast observation and is promising for the direct imaging of an Earth-like exoplanet.

关键词： Earth-like exoplanets dark-hole correction high-contrast coronagraph spgd algorithm

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Performance Optimization of liquid crystal optical phased array beam based on stochastic parallel gradient descent algorithm 7

Performance Optimization of liquid crystal optical phased ar...

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7th International Conference on Optical and Photonic Engineering (icOPEN)

作者： Li Lan-ting Wang Chun-yang Zhang Guang-ping Shi Hong-wei Niu Qi-feng Changchun Univ Sci & Technol Sch Elect & Informat Engn Changchun 130022 Peoples R China Xian Technol Univ Informat Percept & Control Inst Xian 710021 Peoples R China Inner Mongolia Inst Met Mat Ningbo Peoples R China

ISBN: (数字)9781510631601

ISBN: (纸本)9781510631601

Affected by voltage quantification, manufacture technology and environment temperature, the actual deflection accuracy and diffraction efficiency of liquid crystal optical phased arrays (LC-OPA) are in error with the ideal situation when the beam deflected. In this paper, we studied the method of improving the deflection performance of LC-OPA based on stochastic parallel gradient descent (spgd) algorithm, and choose Strehl ratio (SR) as the performance evaluation function for simulation experiments. We analyzed the influence of the disturbance amplitude delta, the gain coefficient gamma and the number of periodic electrodes N on the performance optimization of the spgd algorithm in the LC-OPA beam. Draw the conclusion: When the number of periodic electrodes N is within a certain range, appropriate adjustment of the disturbance amplitude delta and the gain coefficient gamma can achieve better optimization effects, and the larger the deflection angle, the better the optimization effect. When the number of periodic electrodes N is 4, the amplitude of disturbance delta is 0.0009, and the gain coefficient gamma is 0.1, the ideal optimization effect of SR of 0.82 can be achieved, which provides a theoretical basis for improving the large-angle deflection precision and diffraction efficiency of LC-OPA.

关键词： LC-OPA diffraction efficiency spgd algorithm beam deflection

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Study on far-field intensity of phased laser beams with different polarization states 12

Study on far-field intensity of phased laser beams with diff...

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12th International Conference on Information Optics and Photonics (CIOP)

作者： Ren, Guangsen Chen, Qianrong Guo, Hao Yin, Ruiguang Gan, Lin Liang, Weiwei State Key Lab Complex Electromagnet Environm Effe Luoyang 471003 Henan Peoples R China

ISBN: (数字)9781510649903

ISBN: (纸本)9781510649903;9781510649897

Numerical simulation is presented to analyze the influence of nonuniform polarization states on a phase locked laser beams array. Beam propagation factor (BPF) is used to evaluate the quality of the combined beam. For a beams array with different polarization states, spgd algorithm can be used for modulating the phases of the beams to get higher energy concentration degree at far field. The numerical simulation shows that the BPF of a beams array with nonuniform polarization states is smaller than an ideal beams array with uniform polarization states. The average of BPF value decreases with the increase of array number. spgd algorithm corrects the polarized component that contains more energy as priority.

关键词： polarization laser beam combining beams array spgd algorithm

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Magnetic fluid deformable mirror based wavefront sensorless adaptive optics systems 6

Magnetic fluid deformable mirror based wavefront sensorless ...

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6th International Conference on Optical and Photonic Engineering (icOPEN)

作者： Wang, Yuanyuan ZhuZhang Mbemba, Dziki ZhizhengWu Shanghai Univ Dept Precis Mech Engn Shanghai Peoples R China

ISBN: (纸本)9781510622579

Magnetic fluid deformable mirror (MFDM) is a new type of wavefront corrector that features large deformation strokes, smooth continuous mirror surface, low manufacturing cost, and easy scalability. Considering the idea of taking full advantages of the MFDM's stroke strengths and the limitations of the adaptive optics (AO) system with the wavefront sensor, this paper proposes a MFDM based wavefront sensorless adaptive optics system. In order to make the MFDM produce desired deformation to eliminate unknown aberrations, this paper introduces the stochastic parallel gradient descent (spgd) algorithm in the control system. Experimental results show that this spgd algorithm can effectively control the MFDM to compensate for the unknown aberration in a parallel laser beam so that a perfect focused spot is produced on the CCD image.

关键词： Wavefront sensorless adaptive optics Magnetic fluid deformable mirror spgd algorithm

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High accuracy phase retrieval method research based on Shack-Hartmann wavefront sensor

High accuracy phase retrieval method research based on Shack...

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International Symposium on Advanced Optical Design and Manufacturing Technologies / International Symposium on Astronomical Telescope and Instrumentation

作者： Zeng, Wenhua Lv, Yang Ma, Haotong Ning, Yu Du, Shaojun Natl Univ Def Technol Coll Optoelect Sci & Engn Changsha 410073 Hunan Peoples R China Hunan Prov Key Lab High Laser Technol Changsha 410073 Hunan Peoples R China Hunan Prov Collaborat Innovat Ctr High Power Fibe Changsha 410073 Hunan Peoples R China

ISBN: (数字)9781510607675

ISBN: (纸本)9781510607675

The Performance of wavefront aberration detection and recovery, is limited by the spatial resolution in subaperture, especially for the high-order aberration. To improve the accuracy of wavefront reconstruction, our paper focuses more on the phase retrieval using the stochastic parallel gradient descent (spgd) algorithm with lower subaperture. In this paper, the theoretical that Shack-Hartmann wavefront sensor can get a single subaperture high spatial frequency components, which are four-dimensional spatial position and spatial frequency information of the two-dimensional light field is researched. Numerical simulations show that compared with conventional methods, the spgd algorithm can effectively improve the phase retrieval precision of higher-order aberrations, and decrease the influence of the spatial resolution in subaperture. At the same time, by selecting the appropriate algorithm iterative initial value can effectively enhance the speed of wave front reconstruction.

关键词： Shack-Hartmann wavefront sensor spgd algorithm high-order aberration phase retrieval

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Wavefront compensation based on stochastic parallel gradient descent algorithm for Earth observation telescope

Wavefront compensation based on stochastic parallel gradient...

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Conference on Unconventional Imaging and Adaptive Optics

作者： Hirose, M. Miyamura, N. Sato, S. Mizutani, T. Kimura, T. Japan Aerosp Explorat Agcy 2-1-1 Sengen Tsukuba Ibaraki 3058505 Japan Meisei Univ Dept Interdisciplinary Sci & Engn 2-1-1 Hodokubo Hino Tokyo 1918506 Japan

ISBN: (数字)9781510645110

ISBN: (纸本)9781510645110;9781510645103

Wavefront compensation techniques that do not require wavefront sensors are demanded in the on-orbit telescopes on Earth observation satellites. This is especially true for segmented or sparse aperture telescopes that could realize unprecedented high angular resolution. A promising wavefront sensorless approach is the stochastic parallel gradient descent (spgd) algorithm. The wavefront correction by the spgd optimization relies only on the intensity data in the acquired image. However, many previous observation targets are point light sources, not the extended ground scenes generally acquired by Earth observation satellites. This paper derives an efficient wavefront control method for imaging systems for the fast spgd optimization. Wavefront compensation has been demonstrated by experiment on extended objects in single aperture optics, in which a microelectromechanical system deformable mirror controls the wavefront. Subsequent numerical simulations are reported for multi-aperture imaging systems. The paper also discuses a method to reduce the computational cost of spgd optimization.

关键词： MEMS deformable mirror spgd algorithm Earth observation telescope

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Adaptive Beamforming Based On Stochastic Parallel Gradient Descent algorithm For Single Receiver Phased Array 2

Adaptive Beamforming Based On Stochastic Parallel Gradient D...

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2nd International Conference on Systems and Informatics (ICSAI)

作者： Zhao, Haijun Zhang, Jing Yin, Zhiping Hefei Univ Technol Sch Comp & Informat Hefei Anhui Peoples R China Hefei Univ Technol Sch Instrument Sci & Optoelect Engn Hefei 230009 Anhui Peoples R China Heifei Univ Technol Acad Photoelect Technol Hefei Anhui Peoples R China

ISBN: (纸本)9781479954582

In this paper, a phased array antenna system with a single receiver is proposed and Stochastic Parallel Gradient Descent (spgd) algorithm is introduced to implement adaptive beamforming. In this system the power level of the output from the single receiver is the only criterion for beamforming. spgd algorithm searches the optimum phase shift values of the phase shifters to produce a beam pointing to the direction of arrival signal. All phase shifters are perturbed simultaneously and all phase shift values are adjusted in one iteration to improve the convergence rate. The numerical simulation demonstrates the performance of the spgd algorithm used in adaptive beamforming of single receiver phased array.

关键词： phased array antenna adaptive beamforming single receiver spgd algorithm

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Application research of stochastic parallel gradient descent algorithm in adaptive optics system

Application research of stochastic parallel gradient descent...

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2014 International Conference on Future Information Engineering and Manufacturing Science(FIEMS 2014)

作者： Lei Zhang Opto-Electronic Engineering School Changchun University of Science and Technology

ISBN: (纸本)9781138026445

With the expansion of the adaptive optics applications,such as optical communication in the atmosphere is no beacon of light scenarios,and there is a strong flicker of long-range atmospheric transport scenarios,based on the conventional adaptive optics wavefront sensor control technology the application is *** recent years,the sensor-based adaptive front optimize system performance without the direct wave optical control technology,due to the simpUcity and complexity of flashes and other environmental conditions on the adaptability of its hardware implementation,more and more research in the field of adaptive optics *** the early development of adaptive optics to hill climbing and multi-frequency vibration technology as the representative of the search optimization algorithm was introduced adaptive optics control methods in the ***,due to slow convergence and high bandwidth requirements of the system,the hardware complexity,low signal to noise ratio are difficult practical *** algorithm control parameters is simple,good convergence efficiency and stability,we have become the preferred method of optimization.

关键词： adaptive optics spgd algorithm wavefront correction

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High accuracy phase retrieval method research based on Shack-Hartmann wavefront sensor

High accuracy phase retrieval method research based on Shack...

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International Symposium on Optoelectronic Technology and Application 2016(OTA 2016)——Conf.7 Astronomical Telescopes and Instrumentation

作者： Wenhua Zeng Yang Lv Haotong Ma Yu Ning Shaojun Du College of Opto-electric Science and Engineering National University of Denfense Technology

The terrestrial atmosphere degrades the telescope images due to the refractive index changes caused by atmospheric turbulence. To take advantages of the large-diameter telescope for high-resolution im

ISBN: (纸本)9781510607668

关键词： Shack-Hartmann wavefront sensor spgd algorithm high-order aberration phase retrieval

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