Lihua Ruan 1,4Zhiqin Yin 1,2,3,4Shibing Zhou 1,4Weibo Zheng 1,4,*[ ... ]Shaowei Wang 1,2,3,4,**
Author Affiliations
Abstract
1 Shanghai Institute of Technical Physics, Chinese Academy of Sciences Shanghai 200083, P. R. China
2 State Key Laboratory of Infrared Physics, Shanghai Institute of Technical Physics, Chinese Academy of Sciences, Shanghai 200083, P. R. China
3 Shanghai Engineering Research Center of Energy-Saving Coatings Shanghai 200083, P. R. China
4 University of Chinese Academy of Sciences, Beijing 100049, P. R. China
5 Shanghai Tech University, Shanghai 201210, P. R. China
6 School of Physical Science and Technology, ShanghaiTech University, Shanghai 201210, P. R. China
7 School of Information Science and Technology, ShanghaiTech University, Shanghai 201210, China
Visual near-infrared imaging equipment has broad applications in various fields such as venipuncture, facial injections, and safety verification due to its noncontact, compact, and portable design. Currently, most studies utilize near-infrared single-wavelength for image acquisition of veins. However, many substances in the skin, including water, protein, and melanin can create significant background noise, which hinders accurate detection. In this paper, we developed a dual-wavelength imaging system with phase-locked denoising technology to acquire vein image. The signals in the effective region are compared by using the absorption valley and peak of hemoglobin at 700nm and 940nm, respectively. The phase-locked denoising algorithm is applied to decrease the noise and interference of complex surroundings from the images. The imaging results of the vein are successfully extracted in complex noise environment. It is demonstrated that the denoising effect on hand veins imaging can be improved with 57.3% by using our dual-wavelength phase-locked denoising technology. Consequently, this work proposes a novel approach for venous imaging with dual-wavelengths and phase-locked denoising algorithm to extract venous imaging results in complex noisy environment better.
Dual-wavelength phase-locked denoising vein visualization enhancement Journal of Innovative Optical Health Sciences
2024, 17(3): 2350033
1 中国科学院精密测量科学与技术创新研究院, 湖北 武汉 430071
2 中国科学院大学, 北京 100049
为满足同一科研园区内不同建筑之间10 MHz氢钟信号（HCS）长期稳定度共享的需求，提出了一种低成本、集成化的基于光纤链路的10 MHz HCS传递完整解决方案。该方案采用1 GHz的射频信号对激光光强进行调制，利用光纤实现信号传递。通过将远端反射信号与本地信号和频后直接与待传递的HCS分频鉴相，输出误差信号反馈控制1 GHz信号的频率，实现远端1 GHz信号与本地HCS之间的相位锁定，从而使远端1 GHz信号具有与本地HCS相同的频率稳定度；之后再通过分频器在远端生成10 MHz信号，作为射频参考输出。实验验证了该方案的频率传递保真度，该系统在200 m往返光纤上的附加频率稳定度 (艾伦偏差）为1 s平均时间和10000 s平均时间；在20 km传递距离上，附加频率稳定度 (艾伦偏差）为1 s平均时间和10000 s平均时间。研究结果表明该系统的长时间频率传递稳定度优于HCS的频率稳定度，可以满足千米范围内氢钟信号共享的需求。
光通信 氢钟信号传递 光纤 锁相环 噪声补偿 optical communication hydrogen clock signal transferring optical fiber phase-locked loop noise compensation
上海理工大学 光电信息与计算机工程学院，上海 200093
基于全保偏掺铒光纤激光器、锁相环系统和太赫兹测距光路搭建了一套太赫兹双光梳测距系统。所采用的全保偏掺铒光纤激光器重复频率为79.261 MHz。利用压电陶瓷(piezoelectric ceramics, PZT)和步进电机(stepper motor, SM)双级反馈控制的方案，实现了重复频率锁定和重复频率1.54 MHz可调。使用频率计数器对双光梳重复频率锁定效果进行监测，重复频率锁定的峰峰值抖动为±1.5 mHz，抖动标准差为0.4 mHz。将双光梳重频差设置在10 Hz，10 min内重复频率差最大抖动为3 mHz，标准差为0.6 mHz。进一步将异步采样双光梳系统应用于太赫兹测距，测量移动距离的误差为3 μm。该系统具有锁定精度高，稳定性强等优势，有望应用于生物无损检测和工业精密加工中。
双光梳 掺铒光纤激光器 锁相环 重复频率锁定 dual-comb erbium-doped fiber laser phase-locked loop repetition frequency locking 
Author Affiliations
Abstract
1 CAS Key Laboratory of Quantum Information, University of Science and Technology of China, Hefei 230026, China
2 CAS Center for Excellence in Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei 230026, China
3 Hefei National Laboratory, University of Science and Technology of China, Hefei 230088, China
Phase-coherent multi-tone lasers play a critical role in atomic, molecular, and optical physics. Among them, the Raman opeartion laser for manipulating atomic hyperfine qubits requires gigahertz bandwidth and low phase noise to retain long-term coherence. Raman operation lasers generated by directly modulated and frequency-multipled infrared lasers are compact and stable but lack feedback control to actively suppress the phase noise, which limits their performance in practical applications. In this work, we employ a fiber electro-optical modulator driven by a voltage-controlled oscillator (VCO) to modulate a monochromatic laser and employ a second-harmonic generation process to convert it to the visible domain, where the beat note of the Raman operation laser is stabilized by controlling the output frequency of VCO with a digital phase-locked loop (PLL). The low-frequency phase noise is effectively suppressed compared to the scheme without active feedback and it reaches with a 20 kHz loop bandwidth. Furthermore, this compact and robust scheme effectively reduces the system’s complexity and cost, which is promising for extensive application in atomic, molecular, and optical physics.
phase-coherent laser quantum information trapped ion stimulated Raman transition phase-locked loop Chinese Optics Letters
2024, 22(2): 022702
1 南京邮电大学 集成电路科学与工程学院, 南京 210023
2 东南大学 毫米波国家重点实验室, 南京 210096
3 国防科技大学 计算机学院, 长沙 410073
采用 65 nm CMOS工艺, 设计了一种低相噪级联双锁相环毫米波频率综合器。该频率综合器采用两级锁相环级联的结构, 减轻了单级毫米波频率综合器带内和带外相位噪声受带宽的影响。时间数字转换器采用游标卡尺型结构, 改善了PVT变化下时间数字转换器的量化线性度。数字环路滤波器采用自动环路增益控制技术来自适应调节环路带宽, 以提高频率综合器的性能。振荡器采用噪声循环技术, 减小了注入到谐振腔的噪声, 进而改善了振荡器的相位噪声。后仿真结果表明, 在12 V电源电压下, 该频率综合器可输出的频率范围为22~26 GHz, 在输出频率为24 GHz时, 相位噪声为-1048 dBc/Hz @1 MHz, 功耗为468 mW。
全数字锁相环 噪声循环振荡器 亚采样锁相环 级联锁相环 相位噪声 all-digital phase-locked loop noise circulating oscillator sub-sampling phase-locked loop cascaded phase-locked loop phase noise
南京邮电大学 集成电路科学与工程学院， 南京 210023
基于110 nm CMOS工艺设计了一种应用于HDMI接收端电路的宽频带低抖动锁相环。采用一种改进型双环结构电荷泵，在25～250 MHz的宽输入频率范围内实现了快速锁定。通过高相噪性能的伪差分环形振荡器产生了调谐范围为125 MHz～1.25 GHz的时钟信号。仿真实验结果表明，该锁相环的锁定时间小于1.2 μs，在振荡器工作频率为0.8 GHz时，其相位噪声为-100.0 dBc/Hz @1 MHz，输出时钟峰峰值抖动为4.49 ps。
锁相环 宽频带 双环电荷泵 伪差分环形振荡器 phase-locked loop wide band double loop charge pump pseudo-differential ring oscillator
1 广西无线宽带通信与信号处理重点实验室， 广西 桂林 541004
2 成都华微电子科技有限公司， 成都 610041
为满足不同速率的串行收发数据采样需求，基于可重构电荷泵阵列设计了一种低抖动宽带锁相环时钟。根据锁相环倍频系数，自适应匹配电荷泵阵列输出电流，实现了较宽频率变换的低抖动输出时钟。锁相环时钟采用40 nm CMOS工艺设计，面积为367.227*569.344 μm2。测试结果表明，锁相环调谐范围为1~4 GHz，输出时钟均方根抖动为3.01 ps@1.25 GHz和3.98 ps@4 GHz，峰峰值抖动小于0.1UI。
可重构电荷泵 可重构分频器 自偏置锁相环 reconfigurable charge pump reconfigurable frequency divider self-biased phase locked loop
燕山大学信息科学与工程学院河北省特种光纤与光纤传感重点实验室，河北 秦皇岛 066004
针对光频域反射（OFDR）系统中光源调频非线性导致的传感单元定位误差、传感精度低、传感范围窄、系统适应性差等问题，提出了开环校正结合光电锁相环闭环校正电流内调制分布反馈式半导体（DFB）激光器的方法。该方法用于控制DFB激光器连续、快速、大范围频率扫描线性化，使其成为OFDR系统的优质光源，提高OFDR的分辨率。实验结果表明DFB激光器的扫频非线性度由16.55%下降至0.078%，拍频信号中心频率的功率提升了21.1 dB，探测范围由15 m提升至50 m，测量值与实际值的最大误差为3.79 mm，重复性测量的最大标准偏差为112.2 μm。
激光器 分布反馈式半导体激光器 光频域反射 频率扫描线性化 光电锁相环 光学学报
2023, 43(23): 2314001
SPAD阵列的规模不断扩大对读出电路(Read-out Integrated Circuit, ROIC)提出了更高的要求，时间数字转换器(Time to Digital Converter, TDC)是ROIC的核心电路，完成对光子飞行时间(Time-of-Flight, TOF)高精度量化。为避免大规模阵列中高频时钟信号长距离走线而引起的串扰和噪声干扰，抑制初相误差引起的检测精度退化，设计了一种基于内置时钟的ROIC阵列电路，阵列像素间距均为100 µm，内置于各像素内的门控环形振荡器(Gated Ring Oscillator, GRO)独立提供像素TDC所需的高频分相时钟信号，各像素GRO均由像素外置锁相环(Phase Locked Loop, PLL)产生的压控信号控制。由于采用一种基于事件驱动的检测策略，只量化光子事件有效触发的TOF，有效降低了系统功耗。该芯片采用TSMC 0.18 µm 1.8 V标准CMOS工艺制造，测试结果表明：TDC的时间分辨率和量程分别为102 ps和100 ns，微分非线性DNL低于0.8 LSB，积分非线性INL低于1.3 LSB，系统功耗小于59.3 mW。
时间数字转换器 光子飞行时间 门控环形振荡器 锁相环 单光子雪崩光电二极管 time to digital converter time-of-flight gated ring oscillator phase-locked loop SPAD 红外与激光工程
2023, 52(9): 20220896
华中师范大学 物理科学与技术学院PLAC硅像素实验室, 武汉 430079
基于TSMC 180nm工艺设计并流片测试了一款用于高能物理实验的电子读出系统的低噪声、低功耗锁相环芯片。该芯片主要由鉴频鉴相器、电荷泵、环路滤波器、压控振荡器和分频器等子模块组成, 在锁相环电荷泵模块中, 使用共源共栅电流镜结构精准镜像电流以减小电流失配和用运放钳位电压进一步减小相位噪声。测试结果表明, 该锁相环芯片在1.8V电源电压、输入50MHz参考时钟条件下, 可稳定输出200MHz的差分时钟信号, 时钟均方根抖动为2.26ps(0.45mUI), 相位噪声在1MHz频偏处为-105.83dBc/Hz。芯片整体功耗实测为23.4mW, 锁相环核心功耗为2.02mW。
探测器 锁相环 相位噪声 低噪声低功耗 均方根抖动 detector phase-locked loop phase noise low noise and low power consumption root mean square jitter
