原子干涉仪用半导体激光器的智能稳频系统

发布时间：2018-02-20 20:52

本文关键词： 原子干涉仪半导体激光器伺服电路激光调制饱和吸收稳频电磁干扰信噪比长期稳定性　出处：《中国科学院大学(中国科学院武汉物理与数学研究所)》2016年博士论文　论文类型：学位论文

【摘要】：原子干涉仪已经成为一种高精度测量的工具并被广泛应用于科学研究和技术应用领域。半导体激光器作为原子干涉仪的重要组成部分,其频率和幅度稳定度都都直接决定干涉仪的性能。高性能原子干涉仪的发展离不开稳定可靠的激光器系统。本论文以原子干涉仪用半导体激光器的智能稳频系统为题,开展了半导体激光器频率控制的系统性研究工作,取得的创新性成果主要有以下几个方面:(一)设计了数字声光调制器驱动源,编写了控制程序。实验测量了数字声光调制器驱动源的相位噪声,用阿伦方差评估了驱动源的频率稳定性,研究了影响DDS(直接数字式频率合成器)频率稳定度的关键因素。着重设计了 DDS中的关键电路-五阶椭圆带通滤波器,利用网络分析仪分析了五阶椭圆带通滤波器的s参数,结果优于同类商品仪器。(二)设计了一套基于Lock_in(锁相放大)原理的饱和吸收稳伺服稳频电路。研究了外腔稳频半导体激光器的频率、温度响应、线宽等特性。建立了饱和吸收稳频装置,成功地将半导体激光器(DL100/DFB)的输出频率锁定在铷原子的饱和吸收峰上。改善了环路滤波器的衰减特性。用数字PID(比例积分微分)模块替代模拟PID电路,提高了频率锁定的动态范围,提高激光器的长期稳定性,将半导体激光器连续锁定时间由此前的几小时提高到7天以上。(三)设计实现原子干涉仪用半导体激光器智能锁频系统。设计了智能锁频电路,编写了控制程序;利用智能锁频系统实现了激光器的自动锁定,将激光器锁定系统连续运行周期延长至15天以上。(四)设计了基于LDO(Low Dropout Regulator)的超低噪声电源,其时域噪宽低达2mV,频域噪声PSD低至-130dBm,全部低达仪器的测量极限,完全替代锂电池作为敏感电路的电源。并且研究了激光器伺服电路中的电磁干扰问题,抑制了数字模拟混合电路的噪声,最终将伺服电路系统的误差信号的信噪比提高了6倍。
[Abstract]:Atomic interferometer has become a high precision measurement tool and has been widely used in scientific research and technical applications. Semiconductor lasers as an important part of atomic interferometer, Both its frequency and amplitude stability directly determine the performance of the interferometer. The development of high performance atomic interferometer can not be separated from a stable and reliable laser system. The systematic research work on frequency control of semiconductor lasers has been carried out. The main innovative achievements are as follows: (1) the drive source of digital acousto-optic modulator is designed. The phase noise of the drive source of the digital acousto-optic modulator is measured experimentally, and the frequency stability of the drive source is evaluated with the Aron variance. The key factors affecting the frequency stability of DDSs (Direct Digital Frequency synthesizer) are studied. The key circuit in DDS, the Fifth order Elliptic Bandpass filter, is designed and the s parameters of the Fifth order Elliptic Bandpass filter are analyzed by network analyzer. The results are better than that of the same commodity instrument. (2) A set of saturated-absorption-stabilized servo frequency stabilization circuit based on the principle of locked phase locked amplifier is designed, and the frequency and temperature response of the external cavity frequency stabilized semiconductor laser are studied. The saturated-absorption frequency stabilizer is established. The output frequency of the semiconductor laser diode DL100 / DFB is successfully locked on the saturated absorption peak of rubidium atom. The attenuation characteristics of the loop filter are improved by replacing the analog PID circuit with the digital PID (proportional integral differential) module. The dynamic range of frequency locking is improved, and the long-term stability of laser is improved. The continuous locking time of semiconductor laser is increased from several hours to more than 7 days. (3) the intelligent frequency locking system of semiconductor laser for atomic interferometer is designed and the intelligent frequency locking circuit is designed and the control program is compiled. The automatic locking of the laser is realized by using the intelligent frequency locking system. The continuous operation period of the laser locking system is extended to more than 15 days. (4) the ultra-low noise power supply based on LDO(Low Dropout regulator is designed. The time-domain noise width is as low as 2 MV, the frequency domain noise PSD is as low as -130 dBm. the measuring limit of all the low-reach instruments is completely replaced by the lithium battery as the power source of the sensitive circuit. The electromagnetic interference problem in the laser servo circuit is also studied. The noise of the digital analog hybrid circuit is suppressed and the signal-to-noise ratio of the error signal of the servo circuit system is improved by 6 times.
【学位授予单位】：中国科学院大学(中国科学院武汉物理与数学研究所)
【学位级别】：博士
【学位授予年份】：2016
【分类号】：TH744.3;TN248.4

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