共查询到18条相似文献,搜索用时 218 毫秒
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提出了一种新的激光多普勒频移测量方法,该方法以相位调制拍频信号振幅和相位作为自变量定义新函数,并以该函数作为多普勒频移鉴频参量,将两类相位调制激光多普勒频移测量方法结合.理论上将该方法的鉴频曲线、灵敏度曲线以及误差曲线等与两类相位调制方法的相应曲线进行比较,发现该方法不但继承了相位调制拍频信号振幅方法的工作方式,能够对小频移量进行测量,而且吸收了相位调制拍频信号相位方法的测量能力,具有更高的测量灵敏度和动态范围.通过实验对硬目标反射的频移可控信号光进行测量,证明了理论的正确性,而且通过调整平移参数,可以使该方法的测量动态范围提高约26.8%,更适合对高多普勒频移量进行测量. 相似文献
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对相位调制拍频信号随信号光频率变化规律进行分析,发现拍频信号相位参量的频谱包含两个在值域上彼此分开的单调边缘,表明利用拍频信号的相位参量可以进行多普勒频移测量.如果利用拍频信号振幅参量对出射激光进行工作点锁定,其多普勒频移测量范围是Fabry-Perot干涉仪边缘技术的两倍.理论分析拍频信号振幅和相位参量的提取方法,表明基于此拍频信号相位参量的测量方法无需进行信号光能量检测,与Fabry-Perot边缘技术方法相比,结构更简单,且少了一条外部噪音混入的通道.为了对该多普勒频移测量方法定量分析和参量优化,利用误差合成原理以及计算机仿真,推导出其测量误差公式.根据测量原理搭建了实验系统,用频率可调光纤激光器的输出光模拟多普勒频移信号光进行测量,结果表明鉴频参量及其误差分布曲线的测量结果与理论分析相符合. 相似文献
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提出了一种激光多普勒频移测量方法, 此方法利用正弦相位调制使信号光在原频率成分基础上产生正负一阶边带, 再由Fabry-Perot干涉仪对调制光振幅和相位进行调整, 使其产生固定频率的拍频信号, 利用此拍频信号的振幅随频率变化而变化的性质来进行多普勒频移测量. 通过理论分析证明该方法具有很高的测量精度, 加工装调难度不大, 兼顾了普通相干与非相干探测方法的优势. 另外通过实验证明该方法的正确性与可行性, 并通过与普通非相干方式比较发现该方法在测量精度上可以提高 约1个数量级.
关键词:
多普勒频移
相位调制
Fabry-Perot干涉仪
拍频 相似文献
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光载无线技术是解决终端超宽带无线通信的重要方法,光信号与微波/毫米波信号的融合处理技术在光-无线的数据格式转换中至关重要.提出了一种基于相位调制信号光注入Fabry-Perot型半导体激光器实现微波副载波相位调制信号产生的方法.光学注入半导体激光器的输出光场会产生一周期(P1)振荡效应, P1振荡产生的边带实现了相位调制信号光的调制分量的放大,被放大的调制分量与注入光载波在激光器腔内拍频形成微波副载波.注入光相位的变化导致新产生的微波副载波相位变化, 实现了注入信号光相位信息转化为微波副载波相位信息.本系统完成1.3 Gb/s, 2.7 Gb/s, 2 Gb/s光相位调制信号到微波副载波相位调制信号的转换,并测量了微波的单边带相位噪声. 通过光电转换和电域混频将还原出的光基带信号与原信号进行逻辑对比,证明了数据信息转换的正确性. 相似文献
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Parameters of a spectrochronograph that represents a Fabry-Perot interferometer combined with a spatial-time analyzer (a streak camera) are analyzed. Using numerical simulation, time scans of interferograms for bandwidth-limited and phase-modulated pulsed optical signals are obtained. The conditions are determined under which a Fabry-Perot interferometer represents a high-accuracy instrument for measuring the timeresolved spectral dynamics of short optical signals. In particular, an adequate representation of relatively smooth and monotone changes in amplitude and phase characteristics of an optical signal in a spectrochronograph requires that the mode lifetime in a Fabry-Perot interferometer be matched to the time scale of changes in the spectral structure of a pulse being studied. The character of distortions formed in the time-resolved spectral patterns in the case where these conditions are not fulfilled is qualitatively determined, and quantitative estimates of the distortions are presented. The results of the analysis and the numerical calculations show that a spectrochronogram obtained using a Fabry-Perot interferometer and a time analyzer (a streak camera) with parameters corresponding to the criteria formulated in the paper enable one to obtain information on the initial amplitude-phase pattern of a light pulse. 相似文献
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A technique for monitoring interferometric sensors by correlation of the optical signal from the sensor with the signal from a phase-modulated reference interferometer is described. The technique is applied to temperature measurement with a fiber Fabry-Perot sensing head. We extend the 7 degrees C unambiguous measurement range obtained with a 1.3-mum laser diode as the light source to 43 degrees C by adding a second laser diode emitting at 1.55mum . Experimentally, a rms phase-measurement error of +/-0.28rad , corresponding to a temperature error of +/-0.32 degrees C , was achieved with a low-quality multimode Fabry-Perot laser. The phase error was improved to +/-0.14rad , corresponding to a temperature error of +/-0.16 degrees C , by use of a distributed-feedback laser diode. 相似文献
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In this paper we use a superluminescent diode (SLD) as the light source of an interferometer and extract a narrow spectrum from a wide spectrum of the SLD with a Fabry-Perot Etalone (FPE). By varying sinusoidally the distance between the two mirrors of FPE, the central wavelength of the narrow spectrum is scanned sinusoidally. The distance between the mirrors is exactly set by a feedback control system, and sinusoidal phase-modulated SLD light that has a large scanning width of about 10 nm can be obtained with high stability and spatial uniformity. The phase of the interference signal has two different components. One is amplitude Zb of sinusoidal phase modulation, which is proportional to the optical path difference (OPD) and the scanning width. The other is conventional phase α, which provides a fractional value of the OPD in the range of the wavelength. By combining the two values of the OPD obtained from Zb and α, an exact OPD larger than the wavelength can be measure with ment accuracy in α. Characteristics of the interferometer are made clearly through step-profile measurements. 相似文献
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As there exist some problems with the previous laser diode (LD) real-time microvibration measurement interferometers, such as low accuracy, correction before every use, etc., in this paper, we propose a new technique to realize the real-time microvibration measurement by using the LD sinusoidal phase-modulating interferometer, analyze the measurement theory and error, and simulate the measurement accuracy. This interferometer utilizes a circuit to process the interference signal in order to obtain the vibration frequency and amplitude of the detective signal, and a computer is not necessary in it. The influence of the varying light intensity and light path difference on the measurement result can be eliminated. This technique is real-time, convenient, fast, and can enhance the measurement accuracy too. Experiments show that the repeatable measurement accuracy is less than 3.37 nm, and this interferometer can be applied to real-time microvibration measurement of the MEMS. 相似文献
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A sinusoidal phase-modulating fiber-optic interferometer insensitive to the intensity change of the light source 总被引:1,自引:0,他引:1
Xuefeng Wang Xiangzhao Wang Yingming Liu Caini Zhang Danyang Yu 《Optics & Laser Technology》2003,35(3):219-222
In a conventional laser-diode sinusoidal phase-modulating (LD-SPM) interferometer, the wavelength of the LD is modulated by varying its injection current. The intensity modulation concurrent with the wavelength modulation leads to measurement errors. A photothermal-modulation method has been proposed to decrease the intensity change of the LD; however, this method cannot be used to measure vibration with a high frequency, and the beam diameter is too large to be used to measure minute objects. In this paper, we propose LD-SPM fiber-optic interferometer, in which the effect of the intensity change of the light source on measurement is eliminated. The diameter of the light beam is less than 0.5 mm. Using this interferometer, we measured displacements of a mirror driven by a piezoelectric transducer. The measurement repeatability is less than 1 nm. 相似文献
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可调谐半导体激光器在调谐过程中的瞬时光谱特性,如瞬时的波长、调谐率、功率、线型和线宽等参数影响着以激光器为光源的光学测量和光相干通信系统的精度。然而,能够同时测量这些瞬变参数的技术至今未见报道。提出了一个基于时频分析的测量半导体激光器在调谐过程中瞬时光谱参数的方法,利用一个短时延外差测量系统,利用激光器瞬时光谱参数与差拍信号瞬时参数的关系,最终获得了半导体激光器在连续电流调谐过程中的瞬时光谱。测量系统采用了10 cm光程差的Mach-Zehnder干涉仪,调谐电流是幅度为20~120 mA、频率是1 kHz的锯齿波,差拍信号可视为直流信号、载波信号与噪声的叠加,按照短时延相干光测量原理,差拍信号中的直流分量幅度的大小反映了激光器输出光信号的功率;载波信号是一种多项式相位信号,由其频率可以推算激光器输出光谱的中心频率或波长;噪声信号则与激光器输出光谱的线型和线宽相关,通过对噪声信号进行时频分析,可以获知激光器在连续电流调谐过程中每一时刻或每个电流下的瞬时线型、线宽。采用了趋势局部均值分解方法对差拍信号进行了准确分离,并对分离信号分别进行处理,同时获知了半导体激光器在调谐过程中的瞬时输出光功率、光波长、调谐率及线型、线宽。在去掉弛豫部分后截取的整周期差拍信号对应的调谐电流60~115 mA变化范围内,半导体激光器(FRL15DDR0A31-18950, Furukawa)瞬时输出光功率变化范围是5.16~10.6 mW,瞬时光波长变化范围为1 579.2~1 579.6 nm;激光器的瞬时调谐率在0.004 8~0.011 5 nm·mA-1范围内单调变化;线宽是852.55~954.95 kHz,呈非线性随机分布。基于短时延、局部均值分解和时频分析方法的瞬时光谱参数测量系统可以准确得到各瞬时光谱参数,测量结果与激光器的静特性相符,且测量系统结构简单,使我们更深入地理解激光器的工作原理,具有广阔的应用前景。 相似文献
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Frequency-shifted feedback (FSF) lasers have emerged as powerful tools for precision distance metrology. At the output of a Michelson interferometer, the detected rf spectra of the FSF laser light contain a length-dependent heterodyne beat signal whose linewidth ultimately limits the achievable accuracy of length measurements. Here, we demonstrate a narrow-linewidth chirped frequency comb from an FSF Ti:sapphire ring laser seeded by a phase-modulated, ultra-low-phase-noise, single-frequency fiber laser. We experimentally investigate the influence of the seed laser linewidth on the resulting width and shape of the length-dependent rf beat signal. An ultranarrow heterodyne beat linewidth of <20 Hz is observed. 相似文献
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One-dimensional displacements of a moving body are dectected from the phase-modulated beat signal of light, generated by two successive ultrasonic modulators. Measurements of triangular and random displacements are demonstrated using a movable reflection mirror. For a sinusoidal motion its amplitude is measured down to 2.2 Å. 相似文献