High accuracy and time resolution optical transfer delay (OTD) measurement is highly desired in many multi-path applications, such as optical true-time-delay-based array systems and distributed optical sensors. However, the time resolution is usually limited by the frequency range of the probe signal in frequency-multiplexed OTD measurement techniques. Here, we proposed a time-resolution enhanced OTD measurement method based on incoherent optical frequency domain reflectometry (I-OFDR), where an adaptive filter is designed to suppress the spectral leakage from other paths to break the resolution limitation. A weighted least square (WLS) cost function is first established, and then an iteration approach is used to minimize the cost function. Finally, the appropriate filter parameter is obtained according to the convergence results. In a proof-of-concept experiment, the time-domain response of two optical links with a length difference of 900 ps is successfully estimated by applying a probe signal with a bandwidth of 400 MHz. The time resolution is improved by 2.78 times compared to the theoretical resolution limit of the inverse discrete Fourier transform (iDFT) algorithm. In addition, the OTD measurement error is below ±0.8ps. The proposed algorithm provides a novel way to improve the measurement resolution without applying a probe signal with a large bandwidth, avoiding measurement errors induced by the dispersion effect.

桶状抽样型电磁量能器（Electromagnetic Calorimeter，Ecal）是俄罗斯在建的重离子超导同步加速器（Nuclotron-based Ion Collider faсility，NICA）中多功能探测谱仪（Multi-Purpose Detector，MPD）上的一个重要探测器，主要用于探测10 MeV至几个GeV能域内电子和光子的能量、时间、位置信息。基于Geant4软件，使用单能电子研究了入射位置及闪烁体层数对探测器模块（module）能量分辨率的影响，闪烁体层数和电子能量对探测器单元（tower）时间分辨率和Ecal位置分辨率的影响。模拟结果表明：随着电子入射位置由module边缘向中心移动，闪烁体内能量沉积由718 MeV增加至758 MeV；在tower长度为415.5 mm条件下，随着闪烁体层数增加，module能量分辨率变差，tower时间分辨率变好，Ecal位置分辨率变差。在兼顾量能器的各项性能后，tower中闪烁体最佳层数为211层，Ecal能量分辨率好于4.35%，时间分辨率小于112 ps，位置分辨率好于2 mm；在相同条件下，电子能量越高电磁量能器的时间分辨率和位置分辨率越好。

单光子探测在量子信息、生物医学、激光雷达成像等领域具有重要应用前景，InGaAs盖革雪崩焦平面具有单光子探测灵敏度，通过计量光子飞行时间实现距离探测，时间数字转换精度决定整个探测系统的测距精度，是近年来单光子探测领域的研究热点。设计了一款64×64面阵型像素级高分辨低误码时间数字转换阵列电路（Time to Digital Converter, TDC），采用局部共享型高中低三段式异步周期TDC结构。低段位TDC全阵列共享，基于压控延迟链（Voltage Control Delay Line, VCDL）分相时钟实现亚纳秒计时；中高段位每个像素独享，中段位采用分频计数器降低时钟频率，降低阵列整体功耗，高段位采用线性反馈移位寄存器实扩展计时量程并实现计时、数据存储、输出一体化。采用延迟采样方案显著降低了因段间计数时钟不匹配导致的数据锁存误码问题。采用0.18 µm CMOS工艺流片，实测250 MHz参考时钟频率下分辨率0.5 ns，积分非线性−0.4~0.6 LSB，微分非线性−0.4~0.4 LSB，TDC转换单调，有效量程位数13位，20 kHz帧频功耗380.5 mW。