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Multi-wavelength laser active coherent combination

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Chinese Physics B 2012年第5期21卷 247-253页

作者：韩凯许晓军刘泽金 College of Opto-electronic Science and Engineering National University of Defense Technology

A seed laser oscillating at different frequencies is proved to have the potential to mitigate the stimulated Brillouin scattering（SBS） effect in a fiber amplifier,which may increase the emission power of a coherent beam combination（CBC） system *** this study,a basic mathematical model describing the multi-wavelength CBC is proposed on the fundamentals of CBC.A useful method for estimating the combination effect and analysing the feasibility and the validity of the multi-wavelength coherent combination is *** the numerical analysis,accordant results with four-wavelength four-channel CBC experiments are *** calculations of some examples with certain spectra,the unanticipated excellent combination effect with a few frequencies involved is explained,and the dependence of the combination effect on the variance of the amplifier chain length and the channel number is clarified.

关键词： fiber laser coherent beam combination multi-wavelength laser optical path difference

Universal form of the power spectrum of the aero-optical aberration caused by the supersonic turbulent boundary layer

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Chinese Physics B 2014年第10期23卷 118-123页

作者：高穹易仕和姜宗福 College of Photon–Electron Science and Engineering National University of Defense Technology College of Aerospace Science and Engineering National University of Defense Technology

Based on the measurement of one-dimensional （1D） optical path difference （OPD） of the supersonic turbulent bound- ary layer, an analytical form for the power spectrum of the two-dimensional （2D） OPD is obtained with its structure function and under the locally homogeneous isotropic assumption. The universality of this spectrum is argued, and its validity is checked by the comparison with experimental result. The potential applications of this model in theoretical and numerical studies are emphasized. Another contribution of this work is around the application of correlation function to analyzing the statistics of OPD. Based on our results and other results published elsewhere, we show that the OPD is often not stationary, and one should be cautious about using this tool.

关键词： aero-optics supersonic turbulent boundary layer optical path difference power spectrum

Analysing the structure of the optical path length of a supersonic mixing layer by using wavelet methods

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Chinese Physics B 2012年第6期21卷 344-351页

作者：高穹易仕和姜宗福赵玉新谢文科 College of Photon-Electron Science and Engineering National University of Defense Technology College of Aerospace and Material Engineering National University of Defense Technology

The nano-particle-based planar laser scattering （NPLS） technique is used to measure the density distribution in the supersonic mixing layer of the convective Mach number 0.12, and the optical path difference （OPL）, which is quite crucial for the study of aero-optics, is obtained by post processing. Based on the high spatiotemporal resolutions of the NPLS, the structure of the OPL is ana]ysed using wavelet methods. The coherent structures of the OPL are extracted using three methods, including the methods of thresholding the coefficients of the orthogonal wavelet transform and the wavelet packet transform, and preserving a number of wavelet packet coefficients with the largest amplitudes determined by the entropy dimension. Their performances are compared, and the method using the wavelet packet is the best. Based on the viewpoint of multifractals, we study the OPL by the wavelet transform maxima method （WTMM）, and the result indicates that its scaling behaviour is evident.

关键词： optical path difference aero-optics supersonic mixing layer wavelet coherent struc-tures scaling behavior

Dependence of interferogram phase on incident wavenumber and phase stability of Doppler asymmetric spatial heterodyne spectroscopy

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Chinese Physics B 2020年第10期29卷 255-260页

作者： Ya-Fei Zhang Yu-Tao Feng Di Fu Peng-Chong Wang Jian Sun Qing-Lan Bai Xi'an Institute of Optics and Precision Mechanics Chinese Academy of SciencesXi'an 710119China University of Chinese Academy of Sciences Beijing 100049China

Instrument drifts introduce additional phase errors into atmospheric wind measurement of Doppler asymmetric spatial heterodyne spectroscopy (DASH). Aiming at the phase sensitivity of DASH to instrument drifts, in this paper we calculate the optical path difference (OPD) and present an accurate formula of DASH interferogram. By controlling variables in computational ray-tracing simulations and laboratory experiments, it is indicated that initial phase is directly determined by incident wavenumber, OPD offset and field of view (FOV). Accordingly, it is indicated that retrieved phase of DASH is sensitive to slight structural change caused by instrument drift, which provides the proof of necessary-to-track and -correct phase errors from instrument drifts.

关键词： atmospheric wind measurement Doppler asymmetric spatial heterodyne spectroscopy optical path difference interference phase

Fiber Fabry-Perot Demodulation System Based on Dual Fizeau Interferometers

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Photonic Sensors 2023年第2期13卷 56-68页

作者： Deyi KONG Zengyu SONG Ning WANG Zhiqi WANG Peijian HUANG Yong ZHU Jie ZHANG The key Laboratory of Optoelectronic Technology&System(Ministry of Education) Chongqing UniversityChongqing 400044China

In this study,we present a dual-Fizeau-interferometer-based high-speed and wide-range fiber-optic Fabry-Perot(F-P)demodulation *** employ two Fizeau interferometers with air cavity thickness satisfying the quadrature requirement to increase the demodulation speed and broaden the demodulation range in order to address the issues of the existing fiber F-P demodulation system's sluggish demodulation rate and limited *** order to investigate the demodulation properties of the dual-Fizeau-interferometer-based demodulation system,we derive and create a theoretical model of the *** theoretical model,which primarily consists of the structural design of the interferometer and the study of the center wavelength of the light sources and their bandwidth selection,is used to construct the optical structure of the demodulation *** to the calculation results,the demodulated signal exhibits the best contrast ratio when the two light sources'respective center wavelengths are 780nm and 850nm,and their bandwidths are 28nm and 30 ***,we finish evaluating the demodulation system's demodulation performance,parameter calibration,and assembly *** test results demonstrate the constant operation of the demodulation system,an update rate of 100kHz,a demodulation range of 4.74μm,and a cavity length resolution of approximately 5 ***,the system can perform high speed demodulation thanks to the light emitting diode's(LED's)nanosecond level switching speed and the usage of a single point detector.

关键词： Fiber-optic Fabry-Perot sensor Fizeau interferometer LED optical path difference quadrature requirement

A novel polarization interferometer for measuring upper atmospheric winds

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Chinese Physics B 2010年第6期19卷 200-206页

作者：穆廷魁张淳民 MOE Key Laboratory for Nonequilibrium Synthesis and Modulation of Condensed Matter School of ScienceXi'an Jiaotong University

A static polarization interferometer for measuring upper atmospheric winds is presented, based on two Savart plates with their optical axes perpendicular to each other. The principle and characteristics of the interferometer are described. The interferometer with a wide field of view can offer a stable benchmark optical path difference over a specified spectral region of 0.55-0.63μm because there are no quarter wave plates. Since the instrument employs a straight line common-path configuration but without moving parts and slits, it is very compact, simple, inherently robust and has high throughput. The paper is limited to a theoretical analysis.

关键词： polarization interferometer upper atmospheric winds optical path difference

Recent Developments in Fiber Optic Spectral White-Light Interferometry

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Photonic Sensors 2011年第1期1卷 62-71页

作者： Yi JIANG Wenhui DING School of Optoelectronics Beijing Institute of TechnologyBeijing100081China

Recent developments in spectral white-light interferometry(WLI)are ***,the techniques for obtaining optical spectrum are ***,some novel measurement techniques are reviewed,including the improved peak-to-peak WLI,improved wavelength-tracking WLI,Fourier transform WLI,and 3×3 coupler based ***,a hybrid measurement for the intensity-type sensors,interferometric sensors,and fiber Bragg grating sensors is *** is shown that these developments have assisted in the progress of WLI.

关键词： optical fiber sensors white-light interferometry optical path difference fiber Fabry-Perot tunable filter extrinsic Fabry-Perot interferometer

Three Beam interfering Pressure Gauge

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Semiconductor Photonics and Technology 1997年第1期3卷 44-49页

作者： WU Zhaoxia, TANG Xuhui, LIU Li, LI Zhiquan(Yanshan University, Qinhuangdao 066004, CHN)

Abstract: In order to solve the problem of high precision, complete electric insulating detection of the pressure measuring system, we have developed the three - beam interferometer. In this paper, the operation princ... 详细信息

关键词： Fourier Transformation Gauge optical path difference Photodetec-tors Three Beam Interferometer

High-Resolution ＆ High-Speed Rotary Fourier Transform Spectrometer

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High-Resolution ＆ High-Speed Rotary Fourier Transform Spect...