Influence of random fluctuation of field phase on contrast ratio of far field of coherent combined laser beams

LI Song-bai; DOU Ru-hai; SHI Xiao-gang; CHEN Jian-guo

doi:10.3969/j.issn.1001-3806.2010.04.012

In order to analyze the influence of phase random fluctuation on the far field of coherent combined beams,the theoretical ways of Fourier optics method and ergodic hypothesis were employed to study the fringe contrast.The analytic expression of the fringe contrast ratio of coherent combined beam was deduced and the influence of random fluctuation of field phases on the contrast ratio of the far field pattern was numerically simulated successfully.Results show that with the quantity η increasing,the contrast ratio of coherent combined beams increase accordingly.The fringe contrast ratio of the far field pattern decreases when the root mean square of phase δφ enhances.For a fixed standard deviation of the phase's fluctuation and the quantity η,the larger the number of the constituent fields is,the bigger the fringe contrast ratio is.These results are useful for understanding of the characteristic of coherent combined beams.

Influence of random fluctuation of field phase on contrast ratio of far field of coherent combined laser beams

1. College of Electronics and Information Engineering, Sichuan University, Chengdu 610064 China;

2. Department of Physics and Electronics Information Engineering, Yangtze Normal University, Fuling 408100, China

Received Date: 2009-06-12

Accepted Date: 2009-07-21

Available Online: 2010-07-25

Abstract: In order to analyze the influence of phase random fluctuation on the far field of coherent combined beams,the theoretical ways of Fourier optics method and ergodic hypothesis were employed to study the fringe contrast.The analytic expression of the fringe contrast ratio of coherent combined beam was deduced and the influence of random fluctuation of field phases on the contrast ratio of the far field pattern was numerically simulated successfully.Results show that with the quantity η increasing,the contrast ratio of coherent combined beams increase accordingly.The fringe contrast ratio of the far field pattern decreases when the root mean square of phase δφ enhances.For a fixed standard deviation of the phase's fluctuation and the quantity η,the larger the number of the constituent fields is,the bigger the fringe contrast ratio is.These results are useful for understanding of the characteristic of coherent combined beams.

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Reference (14)

[1]	LOU Q H,ZHOU J,WANG Zh J.Analysis of high-power fiber laser weapons[J].Laser Technology,2003,27(3):161-165(in Chinese).
[2]	ZHANG P,GAO L J,WU Zh.A study on the coherent composition of multiple laser beam[J].Journal of Huazhong University of Science & Technology,1997,25(2):66-69(in Chinese).
[3]	ISHAAYA A A,DAVIDSON N,SHIMSHI L,et al.Intracavity coherent addition of Gaussian beam distributions using a planar interferometric coupler[J].A P L,2004,85(12):2187-2189.
[4]	AUGST S J,FAN T Y,SANCHEZ A.Coherent beam combining and phase noise measurements of ytterbium fiber amplifiers[J].Opt Lett,2004,29(5):474-476.
[5]	CHEN H B,YANG H,CHEN J G,et al.Improve output characteristics of diode laser arrays using phase locking[J].Laser Journal,2005,26(3):21-22(in Chinese).
[6]	CHEN Z L,HOU J,ZHOU P,et al.Mutual injection locking of two individual fiber lasers[J].Acta Physica Sinica,2007,56(12):7046-7050(in Chinese).
[7]	XIAO R,HOU J,JIANG Z F.Coherent combining of fiber lasers[J].Laser Technology,2005,29(5):516-519(in Chinese).
[8]	LI Y Zh,QIAN L J,LU D Q,et al.Coherent and incoherent combining of fiber array with hexagonal ring distribution[J].Opt and Laser Technol,2007,39(5):957-963.
[9]	LEHMAN A C,RAFTERY J J,SENIOR J R,et al.Coherence of photonic crystal vertical-cavity surface-emitting laser arrays[J].IEEE J Q E,2007,43(1):25-30.
[10]	ZHOU P,HOU J,CHEN Z L,et al.Comparison for coherent combining and spectrum combining of fiber lasers[J].Laser Technology,2008,32(4):413-416(in Chinese).
[11]	AUTERBORN M,WIESENFELDT K M.Coherent optics:foundamentals and applications[M].New York:Springer Verlag,1993:149-180.
[12]	SHI X M,DOU R H,WANG C G,et al.Using Fourier optics to study features of combined beams in far field[J].High Power Laser and Particle Beams,2007,19(12):1942-1946(in Chinese).
[13]	WANG Zh X.Statistical physics[M].Beijing:Higher Education Press,1956:68-70(in Chinese).
[14]	SHI P Ch,CHEN J G,QIAN L X,et al.Phase-locking observed among high-order lateral modes of a broad-stripe diode array inside an external cavity[J].Opt and Laser Technol,2007,39(5):953-956.

Influence of random fluctuation of field phase on contrast ratio of far field of coherent combined laser beams

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