F⁃P干涉仪差分锁频系统研究

为解决法布里?珀罗（Fabry?Perot, F?P）干涉仪锁频方法响应速度、抗干扰能力、长期稳定性方面存在不足的问题,提出了F?P干涉仪差分锁频方案,将存在频差的双频激光耦合入F?P谐振腔,当激光频差足够小时,两光强信号曲线存在交叉,以两光强信号的差值作为被控量,在交叉点附近构建单调过零函数,作为闭环控制系统的反馈量,实现动态差分锁频控制。基于该方案,搭建了一套F?P干涉仪微位移测量装置并开展实验验证,结果表明该装置能够实现0 ~ 300 nm范围内的微位移测量,位移测量分辨力达到23 pm,验证了F?P干涉仪差分锁频方案的有效性,为推动微位移测量领域的发展提供了重要借鉴。     

锁频环中二阶环路滤波器的设计

锁频环广泛应用于频率误锁问题,达到稳定的跟踪频率.在锁频环中,环路滤波器对于频率误差的滤波作用,使得锁频环可以更好的锁定频率.中首先介绍锁频环的工作原理,继而对环路滤波器进行详细的讨论和研究,最后将设计的滤波器应用到锁频环中用硬件实现.     

"飞秒激光光学频率梳的研究"通过专家鉴定

计本刊讯(记者马靖通讯员卢敬叁)9月12日,由中国计量科学研究院承担的“飞秒激光光学频率梳的研究”顺利通过鉴定委员会专家的鉴定。该研究成果成功将我国633nm氦氖国家激光波长基准的频率直接溯源到国家铯原子时间频率基准,从根本上解决了我国激光波长基准必须通过国际比对才能实现量值溯源的问题。“飞秒激光光学频率梳的研究”是通过飞秒光梳技术使微波频率与光学频率得到链接,实现了激光频率的直接绝对测量,这项技术被科学界视为光频测量领域的突破性成就。“飞秒光梳”技术是世界科技前沿项目,也是计量学研究的重要课题之一。2001年,中…     

地图线状要素注记自动配置的算法与实现

本文探讨了线状要素自动注记的几个关键问题,提出利用注记参考线计算线状要素的注记定位线,同时提出反Douglas算法进行注记参考线的动态分段,利用动态分段的结果集获取线状要素的平滑位置作为候选注记位,在此基础上获取注记中每个字的备选位置以及评分,最后采用禁忌算法解决注记之间的冲突,从而较好地解决了线状要素注记不可见或表达模糊的问题,实现了自动注记输出的完整性和美观性的统一。     

热轧宽带钢卷运输中的自动对中定位研究与应用

介绍了如何采用激光检测器配合激光检测器实现钢卷自动对中定位,从而解决钢卷运输中的问题。     

采用Zeeman效应与饱和吸收法的激光器稳频

由于塞曼效应中性原子的超精细能级在磁场中会产生塞曼分裂,且对于左旋和右旋圆偏振光原子能级的偏移不同,因此利用Zeeman效应的这种特性与饱和吸收相结合的方法对光栅外腔反馈的半导体激光器系统进行稳频。这种方法能够将激光频率稳定地锁在原子吸收谱线的峰值处,锁频后激光器不易失锁,用于激光冷却铷原子实验。     

应用于边带调制PDH激光稳频的信号源设计

基于直接数字频率合成芯片AD9959、锁相环芯片ADF4351,结合开源电子平台Arduino（基于微处理器ATmega328）,建立参考到同一个外部频率参考的多路信号源,能够输出频率为0 Hz～4.4 GHz的正弦波,频率、相位、幅度可以通过USB端口和控制面板灵活控制,通过混频和叠加等手段,产生边带调制PDH激光稳频需要的调制信号和解调信号。该信号源集成度高、成本低且能在实验室条件下替代商品仪器应用于边带调制PDH激光稳频等实验,解决了限制边带调制PDH激光稳频推广应用的一个重要障碍。     

1.5μm光纤通信波段乙炔稳频激光技术研究进展

1.5μm乙炔饱和吸收谱线是国际计量委员会(CIPM)正式推荐的光纤通信波段复现‘米’定义的频率参考标准。乙炔稳频激光依据稳频方法可分为线性吸收和饱和吸收两大类,饱和吸收相比线性吸收,能够消除乙炔分子的多普勒效应,获得线宽更窄、频率稳定度和复现性更高的稳频激光,1s频率稳定度能够达到10^-13量级,波长漂移为10^-12量级。利用13C2H2(ν1+ν3)P(16)谱线,研发的微型气室有望实现稳频激光的全光纤链路传播,为高度集成化、抗干扰能力强的稳频激光源提供了新的发展方向。高性能的1.5μm近红外稳频激光直接为密集波分复用系统、精密光纤传感等多个领域提供波长参考源,结合飞秒激光频率梳技术可进一步完善光纤通信中激光波长量值传递溯源体系,提升激近红外波段光波长的测量能力,为光纤波段的精密测量提供量值保障。     

基于光学锁相环的高稳定度激光稳频方法研究

报道了一种基于光学锁相环的高稳定度激光稳频方法,用于提高可调谐外腔半导体激光器(TECDL)的频率稳定度和准确度。自行研制的光学锁相环电路采用数字鉴相与差分运算相结合的方式获得高灵敏度的鉴频鉴相误差信号,并通过高速模拟PID实现整个系统的闭环锁定。利用该光学锁相环系统进行了TECDL偏频锁定至光学频率梳(OFC)的实验,实验结果表明环路锁定后拍频频率波动在±0.3Hz范围内,偏置频率为50MHz时,光学锁相环系统在1s和1000s积分时间的相对阿伦方差分别为1.5×10^-9和8.5×10^-13。系统锁定后,拍频线宽由500kHz压缩至2kHz。该研究表明采用基于光学锁相环的激光稳频方法可以实现亚Hz级的激光频差控制,通过将TECDL偏频锁定至高稳定度的参考激光源可显著提高其频率稳定度,使其能够满足超精密测量、冷原子/离子干涉测量等领域对激光频率稳定度和准确度的要求。     

显微标尺测量系统的研制

本文介绍了应用TWAIN接口CCD为光电接收器来实现对刻线自动瞄准的简易型显微标尺测量系统 ,配合高分辨力的激光干涉仪和实时图像采集处理系统 ,具有结构简单、成本低、测量准确度高的优点。文中提出三种不同的刻线自动瞄准算法 ,确保系统测量软件的刻线自动瞄准的实现     

Simultaneous injection locking of couples of high-power broad-area lasers driven by a common current source

We experimentally demonstrate the simultaneous injection locking of pairs of high-power broad-area laser diodes in a 19-laser array driven by a common current source. Each pair is injection locked by use of a single-mode low-power semiconductor laser. The frequency and phase locking are verified bythe optical spectrum and the interference pattern between the injection-locked lasers. The influence of frequency detuning on the (simultaneous) injection behavior has been experimentally clarified. We validate a necessary condition for the injection locking of a broad-area laser array.     

Simple method for frequency locking of an extended-cavity diode laser

We have developed an extended-cavity tunable diode laser system that has a small linewidth and a large output power (more than 90% of the free-running power) whose operating frequency can be conveniently locked to a transition line of Rb atoms. Based on flat-mirror feedback and frequency self-locking and with weak feedback, we have achieved a continuous frequency detuning range greater than 900 MHz and a short-time linewidth stability of better than 0.4%. By using a two-step locking procedure we not only can lock the laser frequency but also can detune the frequency to any desired value. The locking is quite sturdy and rugged.     

Influence of detuned injection locking on the relaxation oscillation frequency of a multimode semiconductor laser

Abstract

The injection locking characteristics of a multi-mode semiconductor laser are considered. A formalism is developed to investigate the stability properties of an arbitrary laser mode subject to optical injection. The formalism is used to show that the relaxation oscillation frequency (ROF) in a semiconductor laser subject to optical injection is increased relative to that of the free running laser diode. Methods of utilizing positive detuning to determine the best approach of increasing the ROF of a semiconductor laser via injection locking are considered.     

Frequency locking of tunable diode lasers to a rubidium-stabilized ring-cavity resonator

We demonstrate a technique for locking the frequency of a tunable diode laser to a ring-cavity resonator. The resonator is stabilized to a diode laser that is in turn locked to an atomic transition in rubidium, thus giving it absolute frequency calibration. The principal advantage of the ring-cavity design is that there is no feedback destabilization of the laser. The cavity has a free-spectral range of 1.3 GHz and Q of approximately 35, which provides robust locking of the laser. The locked laser is able to track large scans of the cavity.     

GHz重复频率固体飞秒激光技术进展及应用前景

针对惯性仪表的复合校准问题,设计了基于离心-温度复合装置的自学习切换控制方法,实现了高精度、高均匀性的温度场控制。根据离心机不同工况下的温度箱控制系统结构不同,切换控制方案可满足系统在高低温下的精度要求,自学习PID控制算法解决了控制过程中存在的温度波动问题。离心机旋转状态下和非旋转状态下的实验结果表明：该控制系统性能良好,在-55～80 ℃内的温度控制误差在±0.1 ℃之内。     

干扰吸收峰影响下TDLAS温度测量方法研究

固体飞秒激光器以其体积小、成本低、使用寿命长、稳定性高、技术较为成熟等特点,受到市场的广泛青睐。重复频率是飞秒激光器的一个重要参数,在实际应用中,高重复频率能带来高效率、高精度等诸多重要优势。本文介绍了SESAM锁模、KLM锁模、高次谐波锁模等常用的GHz固体飞秒激光器锁模技术及发展情况,阐述了GHz飞秒光源在激光加工、距离测量、光谱测量等应用场景中突出的性能优势,并对GHz重复频率固体飞秒激光技术的发展方向进行了预测,为推动GHz重复频率固体激光器技术的完善与提升提供借鉴。     

Frequency Stability at the Kilohertz Level of a Rubidium-Locked Diode Laser at 192.114 THz

The frequency stability of a 1560-nm diode laser, whose second harmonic was locked to (87)Rb sub-Doppler lines, was characterized by measuring the beat frequency relative to a 780-nm reference laser that was locked to sub-Doppler lines of another rubidium cell. The square root of the Allan variance reached a minimum value of 7.5 x 10(-12) in 1 s, which corresponded to frequency variations of 1.44 kHz for the 1560-nm laser. The frequency reproducibility of the system was approximately 1 x 10(-9). These values are better than those that can be achieved by locking to Doppler-broadened transitions at the 1550-nm wavelength band.     

Tunable and frequency-stabilized diode laser with a Doppler-free two-photon zeeman lock

We describe frequency locking of a diode laser to a two-photon transition of rubidium using the Zeeman modulation technique. We locked and tuned the laser frequency by modulating and shifting the two-photon transition frequency with ac and dc magnetic fields. We achieved a linewidth of 500 kHz and continuous tunability over 280 MHz with no laser frequency modulation.