【作者】 邓海峡；

【导师】 王宝光；

【作者基本信息】 天津大学 ， 精密仪器及机械， 2009， 硕士

【摘要】 光学传感测量是一种非接触式测量,具有高精度,稳定性好等优点,在精密测量领域发挥着重要的作用。在众多的光学测量中,以激光干涉法应用最为广泛。近年来以垂直腔面发射激光器(VCSEL)作为新兴的激光光源受到了人们的广泛关注,以其发射角小、极短的光学谐振腔易于实现动态单模工作、极低的功耗等优点已经成为光学信息处理、光通讯的主要光源。VCSEL加速了激光自混合干涉(SMI)技术的应用发展,自混合干涉的主要优点是系统简单、结构紧凑、易准直,解决了传统干涉光路的复杂、尺寸大的问题。本文对垂直激光器自混合技术进行深入研究,主要研究内容包括以下几个方面:1.用三镜腔模型和激光速率方程深入研究了激光自混合效应的基本理论,建立了自混合干涉的数学模型,为后期的实验和分析奠定理论基础。2.建立单模VCSEL自混合测振实验装置,设计系统的光电信号处理电路。采用单模VCSEL代替普通半导体激光器,使得外部光路简单紧凑,提高了测振精度。3.研究了外腔振动下的自混合信号的特点。通过改变振动源的频率、振幅和波形进行振动传感测量实验,观察到了相应的自混合干涉信号,并对实验结果进行了理论分析。4.基于信号的统计特性,利用短时傅立叶变换获取自混合信号的时频分布特征。5.根据傅立叶变换的信息,利用比值法对频谱进行校正。6.根据表征信号奇异点的特征,对多普勒信号脱落引起的频率奇异点进行跟踪识别,并拟合修正,进一步提高信号时频分布精度。7.采用扬声器作为振动源,通过一系列对比实验,定性分析系统测试性能。更多还原

【Abstract】 Optical sensing and measuring technologies are non-contacted;they have a lot of advantages such as high accuracy,perfect stability,etc and play an important role in the field of metrological measurements of various optical sensing and measuring methods.Laser interferometry is the most widely used.Vertical cavity surface emitting lasrs(VCSEL) as a new laser light source has received a huge amount of attention in recent years. VCSEL have become the ideal light sources for optical signal processing and optical communication by their attracvtive such as low emission angle , inherent single longitudinal mode operation due to short optical resonator and low power consumption. VCSEL accelerate the application development of laser self-mixing interference(SMI).Its main advantages include simplicity, compact conformation and easy alignment providing a better solution to the problems of complexity and large size of the conventional interferometric systems.The mechanism and technology of the SMI based on vibration sensing and measuring has been studied theoretically and experimentally in this thesis. The main contents are included as follows:1.The fundamental principle of sensing technology have been deseribed based on the self-mixinge effet of laser diode using three-mirror model and rate equation. It has laid the theoretic foundation for the latter part of the experiment and analysis.2.Single mode VCSEL laser doppler vibration experimental setup is constructed and optoelectronic singal proeessing circuits of the system is designed. The precision vibration has been improved for using single mode VCSEL in place of common semiconductor.3.The characteristic of the SMI of the external cavity vibration has been studied. The vibration measuring experiments had been carried out by changing the frequency,amplitude and waveform of the vibrating object,respectively. The corresponding SMI singals had been observed experimentally and the experiment results had been analyzed.4.On the basis of statistical characteristic of signal short time discrete Fourier transform has been used to obtain time-frequency distribution of Doppler signal.5.According to the information of Fourier transform, ratio regulate method has been employed to correct the frequency of maximum spectrum in the result of Doppler signal’s Fourier transform.6.According to the spread characteristic of singular point’s Modulus Maximum from big scale to small , the frequency singular point caused by Doppler signal’s drop-off can be identified. The accuracy of time-frequency distribution can be improved.7.The system uses a speaker as the source of the vibration.It has been analysised test performance of the system through a series of comparative experiments更多还原