共查询到19条相似文献,搜索用时 171 毫秒
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介绍了采用激光-多普勒振干涉系统绝对复现大位移、宽脉冲的冲击加速度量值的方法,说明了干涉系统的构成及原理。这种方法适合于长距离干涉测量和动态干涉测量。 相似文献
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Zhang Zhiying 《计测技术》1998,(2)
介绍了采用激光─多普勒偏振于涉系统绝对复现大位移、宽脉冲的冲击加速度量值的方法,说明了干涉系统的构成及原理。这种方法适合于长距离干涉测量和动态干涉测量。 相似文献
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激光外差干涉是新一代水声声压基准的主要技术,光学干涉系统中的信号解调算法直接影响质点振速和声压量值。为准确得到测量结果,详细介绍了如何从多普勒信号中得到水质点振速的过零点解调算法,并建立了一套在线解调系统。该系统利用信号源产生两路相互正交的多普勒信号模拟光电二极管的输出,再经差分放大电路后进入示波器进行数据采集,最后由主机软件在线读取数据并完成质点振速解调。实验结果有效验证了过零点算法和解调系统的正确性和稳定性,所设计的过零点解调系统可直接应用于激光外差干涉法复现水声声压。 相似文献
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一、概述和技术要求在电子束曝光机中,激光干涉仪测量工件台的位置精度是获得高精度掩模版图形的重要环节。因此对激光定位干涉系统不仅要 1、组合干涉分光镜与长条直角反射镜相对位置的正确,即使组合干涉分光镜的棱线垂直于长条直角反射镜镜面棱线,不垂直度小于30角秒,以保证干涉圈的质量。 相似文献
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A compensation technique for reducing the effect of nonlinear optical frequency swept in an optical frequency-domain reflectometer (OFDR) is proposed. The instantaneous sweep optical frequency of an OFDR laser source is directly obtained by analysis of the interference signal from an auxiliary interferometer with a Hilbert transformation. Beating OFDR data from a main interferometer are regenerated with respect to the measured instantaneous optical frequency. We show that this technique dramatically improves the spatial resolution of a conventional OFDR and can be applied to an optical frequency-domain medical imaging system to eliminate the problem of a nonlinear frequency sweep effect. 相似文献
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A phase-shifting laser diode interferometer that uses direct pulse modulation is proposed and demonstrated. We found that a laser beam with a wide range of wavelength variation at constant optical power could be generated when a pulsed current was injected into the laser diode. We constructed a highly accurate interferometer by using a pair of interferometers. Several experiments, such as observations of temporal interference signals and spatial interferograms, measurement of a concave mirror, and duplicate measurements, confirmed the characteristics of pulse modulation and demonstrated the effectiveness of our technique. 相似文献
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Abstract We demonstrate a novel active fibre-optic interferometric sensor based on a temperature-stabilized low-finesse fibre-optic Fabry-Perot. In this apparatus, information on the optical phase was extracted from the frequency shift of the He-Ne laser of which the cavity length was thermally tuned to compensate change in the interference signal. It is shown that an improvement in the stability of the interference signal by two orders of magnitudes can be realized. The tracking achievable between the Fabry-Perot interferometer and the laser was better than 1 part in 108. That is, the relative frequency stability of the laser was ? 1·0 × 10?8 over an interval of tens of minutes. Detection of a change of 5 nm in the optical path length of the fibre-optic Fabry-Perot was also demonstrated. The dynamic range of this interferometer is over 40 dB and the linearity characteristics are excellent. These performance characteristics were limited by the long-term thermal drift of the apparatus, not the low reflectivity of the fibre ends of the Fabry-Perot interferometer. 相似文献
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针对目前国内激光测振系统价格昂贵、使用不便的问题,采用1 550 nm波段成熟的窄线宽光源和光纤元器件研制了一套低成本的全光纤激光测振系统原理样机。此原理样机光路部分采用马赫?泽德干涉仪结构,搭建了外差式激光干涉光路,参考光被40 MHz的声光调制器调制,与测量光在光电探测器表面发生干涉,产生原始的激光多普勒信号;信号解调部分采用相位解调法对原始激光多普勒信号进行解调,得到振动目标的运动特性,包括位移、速度和加速度信息。采用本单位的振动标准装置对其性能进行了测试,实验结果表明:在10 ~ 2 000 Hz的中低频振动范围内,1 550 nm全光纤激光多普勒测振系统峰值位移、速度和加速度的测量误差在-0.6% ~ 0.7%内。该系统在中低频段具有较高的测量准确度,且成本相对较低、操作便捷,具有技术借鉴价值。 相似文献
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A two-wavelength interferometer with a fractional fringe technique (the method of coincidence) has been constructed by using dual frequency-ramped laser diodes. The respective wavelengths of two optical phases were measured by the heterodyne technique. The detected two phases are employed with real-time electronic processing to produce two signals that correspond to the integer and the fractional fringe numbers at a single wavelength. These summed signals can yield a synthetic phase having a single-wavelength resolution. The upper limits for the measurement accuracy are theoretically analyzed. 相似文献