Y型腔正交偏振双频激光器及微力测量研究

发布时间：2018-06-04 17:44

本文选题：一体化Y型腔正交偏振双频激光器 + 频差闭锁　；参考：《国防科学技术大学》2015年硕士论文

【摘要】：双频激光器广泛应用于干涉和光学传感测量领域,其测量精度和量程决定于双频激光器频差稳定性以及频差输出范围。Y型腔正交偏振双频激光器具有零频差闭锁、频差输出范围大、高频差稳定性等潜在优势,有望在高速大量值以及精密测量中发挥重要作用。本文主要研究一体化Y型腔正交偏振双频激光器频差闭锁、频差稳定性及其在微力测量中的应用。为进一步改善Y型腔正交偏振双频激光器性能,推进其在精密加速度、微力测量等领域的应用提供理论与实验依据。首先对影响Y型腔正交偏振双频激光器闭锁阈值频差的因素进行了系统分析。理论分析了工作点、泵浦电流以及损耗等因素对激光器闭锁阈值频差影响,实验重点研究了泵浦电流和工作点对闭锁阈值频差影响。在电流允许范围内,激光器闭锁阈值频差随泵浦电流值增大而减小;工作点越靠近增益曲线中心,激光器闭锁阈值频差越小。泵浦电流大于2.2mA时,调节激光器公共腔长获得最佳工作点,激光器闭锁阈值频差可降至几MHz。系统研究了磁场抑制Y型腔正交偏振双频激光器频差闭锁问题。从磁光效应出发,理论分析了磁场抑制双频激光器频差闭锁原理。利用方体线圈产生均匀磁场,通过Ansoft Maxwell软件对方体线圈内磁场分布进行了仿真分析。对横向磁场抑制Y型腔正交偏振双频激光器频差闭锁效果进行了实验研究,结果表明,泵浦电流为1.8mA条件下,当磁场强度大于10mT时,激光器闭锁阈值频差可降至几十KHz,实现了激光器的零频差闭锁。对Y型腔正交偏振双频激光器频差稳定性进行了研究。理论与实验研究表明,环境气流、泵浦电流稳定性以及温度分布是影响双频激光器频差稳定性主要因素。激光器自身热源带来的两子腔温度梯度随机变化成为限制激光器频差稳定性提高的关键因素。利用Y型腔正交偏振双频激光器搭建了气体膜盒结构微力测量系统,开展了静态微力测量实验研究。采用大挠度下的集中力模型对微力测量原理进行了理论推导,通过实验对微力测量系统性能进行了分析。实验表明,当力值小于7mN时,激光器输出频差变化量与待测力间成线性关系,比例因子为1.23842×10~9Hz/N;待测力大于7mN后,激光器频差变化量发生非线性变化。激光器频差漂移及待测力作用点成为影响微力测量系统精度的主要因素。
[Abstract]:Dual-frequency lasers are widely used in the fields of interferometry and optical sensing measurement. The accuracy and range of measurement are determined by the stability of the frequency difference of the dual-frequency laser and the output range of the frequency difference. Y-cavity orthogonal polarization dual-frequency laser has zero frequency difference locking. The potential advantages of wide output range of frequency difference and stability of high frequency difference are expected to play an important role in high speed and large value and precision measurement. In this paper, the frequency difference locking, frequency difference stability and its application in micro-force measurement of an integrated Y-cavity quadrature polarization dual-frequency laser are studied. It provides theoretical and experimental basis for further improving the performance of Y-cavity orthogonal polarization dual-frequency laser and promoting its application in the fields of precision acceleration and micro-force measurement. Firstly, the factors influencing the locking threshold frequency difference of Y cavity orthogonal polarization dual frequency laser are analyzed systematically. The effects of operating point, pump current and loss on the frequency difference of laser latchup threshold are analyzed theoretically. The effects of pump current and operating point on the latch-up threshold frequency difference are studied in the experiment. The threshold frequency difference of the laser latching decreases with the increase of the pump current, and the closer the operating point is to the center of the gain curve, the smaller the frequency difference of the latching threshold is. When the pump current is greater than 2.2mA, the optimal operating point can be obtained by adjusting the length of the common cavity, and the frequency difference of the latching threshold can be reduced to several MHz. The problem of frequency difference latchup of Y-cavity orthogonal polarization dual-frequency laser with magnetic field suppression is studied systematically. Based on the magneto-optic effect, the principle of frequency difference latchup of magnetic field suppression dual frequency laser is theoretically analyzed. The uniform magnetic field is generated by the square coil, and the magnetic field distribution in the coils is simulated by Ansoft Maxwell software. The effect of transverse magnetic field on the suppression of frequency difference latchup of Y-cavity orthogonal polarization dual-frequency laser is studied experimentally. The results show that when the pump current is 1.8mA, the magnetic field intensity is greater than 10mT. The threshold frequency difference of laser latching can be reduced to dozens of kHz, and the zero frequency difference latchup of laser is realized. The frequency difference stability of Y cavity orthogonal polarization dual frequency laser is studied. Theoretical and experimental studies show that the ambient flow, pump current stability and temperature distribution are the main factors affecting the stability of the frequency difference of the dual-frequency laser. The random variation of the temperature gradient of the two subcavities caused by the laser's own heat source is the key factor to limit the stability of the laser frequency difference. Using Y-cavity orthogonal polarization dual-frequency laser, a gas diaphragm structure micro-force measurement system is built, and the static micro-force measurement experiment is carried out. The principle of micro-force measurement is derived theoretically by using the concentrated force model under large deflection, and the performance of micro-force measurement system is analyzed by experiments. The experimental results show that when the force value is less than 7mN, there is a linear relationship between the output frequency difference and the force to be measured, and the ratio factor is 1.23842 脳 10 ~ (9) Hz / N, and when the force is larger than 7mN, the variation of laser frequency difference is nonlinear. The laser frequency shift and the application point of the force to be measured are the main factors that affect the precision of the micro-force measurement system.
【学位授予单位】：国防科学技术大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TN248

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