单频全固态激光器稳频技术研究
文献类型：学位论文
| 作者 | 孙旭涛 |
| 学位类别 | 博士 |
| 答辩日期 | 2008 |
| 授予单位 | 中国科学院上海光学精密机械研究所 |
| 导师 | 陈卫标 |
| 关键词 | 单频全固态激光器 种子注入激光器 稳频 PDH稳频技术 共焦法珀干涉仪 |
| 其他题名 | Study of Frequency Stabilization of Single Frequency All-Solid-State Laser |
| 中文摘要 | 单频全固态激光器在激光雷达、高分辨率激光光谱、引力波探测、相干通信等领域有着广泛的应用。在这些领域中，不仅要求激光单频输出，还要求激光具有较高的频率稳定性。在多普勒测风激光雷达中，激光输出频率稳定性直接决定了测风精度。根据本课题组正在研发的紫外直接探测多普勒激光测风雷达的需求，激光频率抖动必须低于1MHz，才能满足低于0.5m/s的风速误差的要求。在本篇论文中，重点探讨直接探测多普勒激光雷达系统中的种子注入激光器种子源的稳频方法和技术，使其满足这一要求。 激光稳频关键的问题是选取频率标准，本文选用共焦法珀干涉仪为频率标准开展稳频工作，主要考虑其具有较好的普适性。通过对三种不同材料制成的共焦法珀干涉仪中心频率随温度漂移情况的分析比较，选用零膨胀微晶玻璃材料制作共焦法珀干涉仪，腔镜和隔离器通过光胶的方式进行组合，腔长200mm，两腔镜凹面镀有高反射膜，反射率为99.88%，面型精度优于λ/10。将干涉仪置于双层密封温控箱中，使用基于PID温控器的两级温控系统进行温控，精度可以达到±0.002℃，因此具有很高的温度稳定性。经过实验测量，共焦法珀干涉仪的自由光谱范围为374MHz，透射谱半宽度为1.7MHz，精细度为220。 文中对基于共焦法珀干涉仪的三种稳频方案进行了理论分析，分别求出了各种方案的鉴频曲线。经过比较，PDH稳频技术具有高灵敏度，宽控制范围以及高信噪比，因此选用该方案对激光进行稳频。建立了PDH方案的理论模型，对相关参数进行了优化。设计和制作了稳频系统中的部分模拟电路，得到鉴频曲线。使用数据采集卡采集鉴频信号，用LabVIEW软件编写了PI控制器作为伺服系统对鉴频信号进行处理后，经过DA变换反馈到压电陶瓷，进行频率控制。 本文完成了整个稳频系统的软硬件，并且根据上述技术对直接探测的多普勒激光雷达中的种子激光器进行了稳频实验。实验中的误差信号实时记录在计算机中，通过鉴频曲线计算出种子激光器在1秒钟内相对频率漂移低于25KHz，1小时内相对频率漂移低于55KHz，满足了系统对稳频的要求。 最后提出了测量共焦法珀干涉仪的频率稳定性的方法。选用一台锁定在碘分子吸收谱线上的双频激光器作为频率标准与锁定在共焦法珀干涉仪的激光进行拍频，采集两激光的混频信号，利用LabVIEW软件编写程序对混频信号进行频谱分析，以拍频率的稳定性衡量共焦法珀干涉仪的频率稳定性。 |
| 英文摘要 | Single frequency all-solid-state laser are attractive sources for laser lidar, high-resolution laser spectroscopy, gravity-wave detection, coherent communication, and so on. In these applications, not only the single frequency but also high frequency stability is required. In Doppler wind lidar, the frequency stability of laser source is a key factor for the accuracy of wind speed’s measurement. According to the requirement of the underdeveloping ultra-violent direct-detection Doppler wind lidar in our group, the frequency drift should be less than 1MHz to satisfy the velocity accuracy of less than 0.5 m/s. In this dissertation, the frequency stabilty’s theory and technique of the master laser is studied for the injection-seeding all solid-state laser of Doppler wind lidar. For the frequency stabilization of laser, the choice of frequency standard is most important. In this dissertation, the laser frequency is stabilized to a high finess confocal Fabry-Perot interferometer (FPI) due to its wider application. After analyzing of the center frequency jitter of confocal Fabry-Perot interferometers with three different optical materiel due to temperature fluctuation，the ZERODUR is selected to construct the confocal FPI. Both the cavity mirrors and spacer are same ZERODUR, and connected with the technique of optical bonding. The cavity length is 200mm, and the reflection of the surface at 1064 nm is 99.88%. The surface is polished with a flatness of less than one wavelength of ten. The confocal Fabry-Perot interferometer is installed in a double cell temperature controlled chamber. The temperature is controlled by a two-stage PID controller, the accuracy of less than 0.002 k is obtained. The experiment results indicate that the free spectral range of 374 MHz and the linewidth of 1.7 MHz, and the cooresponding finesse is about 220. Three techniques of laser frequency stabilization with Fabry-Perot interferometer is overview theoretically. By comparing the error signal, Pound-Drever-Hall technique is adopted due to the highest steepness at the lock point, the most intense signal and widest control range. The controlling model of Pound-Drever-Hall frequency stabilization for the injection-locked solid-state laser is established. The parameter in the controlling loop is analyzed and optimized. The circuit for frequency stabilization is designed and developed. The error signal of the controlling loop is digitized by a data acquisition card of 16 bit. The digiztied signal is processed by a virtual proportional controller and a virtual integrator written in LabVIEW language. According the processing result, a feedback voltage signal is output from a analog to digital converter, and connected to PZT controller of the seeder laser for frequency change. The hardware and software of frequency-stablitation system is developed. The frequency of seeder laser of direct-detection Doppler lidar is stabilized with the above technique. The error signal is record in real-time during experiments. Therefore,the relative frequency drift of the seeder laser is calculated with the results of less than 25 kHz in 1s and less than 55kHz in 1h. The results are satisfied with the requirement of Doppler lidar. At last, the frequency stability of the confocal Fabry-Perot interferometer is studied. An I2-locked double frequency Nd:YAG laser is served as frequency standard. The frequency-mixing signal is acquired by a data acquisition card. The spectral analysis of the signal was carried out by a LabVIEW program. The frequency stability of the confocal Fabry-Perot interferometer is characterized by the stability of the heterodyne beat frequency. |
| 语种 | 中文 |
| 源URL | [http://ir.siom.ac.cn/handle/181231/15235]  |
| 专题 | 上海光学精密机械研究所_学位论文 |
| 推荐引用方式 GB/T 7714 | 孙旭涛. 单频全固态激光器稳频技术研究[D]. 中国科学院上海光学精密机械研究所. 2008. |
入库方式： OAI收割
来源：上海光学精密机械研究所
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