Fast and stable phase control is essential for many applications in optics. Here, we propose an all-fiber all-optical phase modulation scheme based on a Fabry–Perot interferometer (FPI) and an Er/Yb co-doped fiber (EYDF). By using the EYDF as an F-P cavity via rational design, a phase shift with a modulation sensitivity of 0.0312π/mW is introduced to the modulator. The phase shifts in the EYDF consist of a thermal phase shift and a nonlinear phase shift with a ratio of 19:1, and the corresponding temporal responses of the modulation are 204 ms and 2.5 ms, respectively. In addition, the compact FPI is encapsulated to provide excellent stability for the modulator.

Ultraviolet (UV) imaging enables a diverse array of applications, such as material composition analysis, biological fluorescence imaging, and detecting defects in semiconductor manufacturing. However, scientific-grade UV cameras with high quantum efficiency are expensive and include complex thermoelectric cooling systems. Here, we demonstrate a UV computational ghost imaging (UV-CGI) method to provide a cost-effective UV imaging and detection strategy. By applying spatial–temporal illumination patterns and using a 325 nm laser source, a single-pixel detector is enough to reconstruct the images of objects. We use UV-CGI to distinguish four UV-sensitive sunscreen areas with different densities on a sample. Furthermore, we demonstrate dark-field UV-CGI in both transmission and reflection schemes. By only collecting the scattered light from objects, we can detect the edges of pure phase objects and small scratches on a compact disc. Our results showcase a feasible low-cost solution for nondestructive UV imaging and detection. By combining it with other imaging techniques, such as hyperspectral imaging or time-resolved imaging, a compact and versatile UV computational imaging platform may be realized for future applications.

大气化学实验课程建设需求非常急迫，但配套实验教材却较为缺乏。该文介绍了《大气化学实验》教材的思路、特色和编写实践。该教材凸显了大气科学学科特点，既包含参照国标方法的基础性业务部门标准实验，又突出引入大型仪器设备的热点前沿实验技术方法，内容基本覆盖大气化学理论知识点，鼓励自主设计实验，旨在帮助培养大气科学实用型和创新型本科人才。该教材的建设，有望解决大气化学实验教材不足的问题，为本课程及相关课程建设提供参考和借鉴。

针对现有光传送网（OTN）专线承载网络存在的时延性能差、业务开通效率低以及网络智能化程度低等问题，文章提出了新一代政企专线承载网络组网策略，给出了100/200 Gbit/s、分组增强型OTN、OTN集群和可重构光分插复用器（ROADM）/光交叉连接（OXC）等传输新技术应用的建议，并将相关成果应用在某运营商政企专线承载网络商用部署中。结果表明，新一代政企专线承载网络具有显著的经济和社会效益，该运营商网络重点金融方向时延性能达到了业内领先，专线业务开通平均时长由以往60天缩短至15天，同时还具备业务端到端自动开通能力。

雨天图像会影响计算机视觉任务的效果与精度。雨天图像常常包含来自不同方向、大小、形状的雨点或雨痕，在对这些雨点、雨痕进行去除时，现有的方法往往没有考虑到雨天图像不同精细尺度下的特征信息，仅采用单一尺度进行图像去雨存在很大缺陷，无法恢复出足够清晰的视觉任务图像。受益于卷积神经网络架构的强大特征提取能力，本文提出了一种端到端的多级联递进卷积结构算子，该算子包含4层卷积层，通过阶梯化连接构成一个整体模块，该模块可以针对多尺度场景下的雨天进行特征提取并整合。将该算子模块嵌入到渐进循环网络结构中，利用循环结构多次去除雨纹，最终有效还原出接近真实图像的无雨图像。该方法在现有的人工合成雨图数据集Rain100H、Rain100L、Rain800与自动驾驶领域合成雨图数据集BDD1000上进行了对比实验。实验结果表明，该算法在4个数据集上的PSNR值达到了30.70，37.91，27.63，35.74 dB，SSIM值达到了0.914，0.980，0.894，0.977。通过真实雨图数据集去雨结果的可视化展示，充分验证了本文方法在去雨任务上的有效性。

In this Letter, the optical amplification characteristics of the home-made Bi/P co-doped silica fiber were systematically explored in the range of 1270–1360 nm. The maximum gain of 24.6 dB was obtained in the single-pass amplification device, and then improved to 38.3 dB in the double-pass amplification device for -30dBm signal power. In addition, we simultaneously investigated the laser performance of the fiber with the linear cavity. A slope efficiency of 16.4% at ∼1313nm was obtained with a maximum output power of about 133 mW under the input pump power of 869 mW at 1240 nm. As far as we know, it is the first laser reported based on the bismuth-doped fiber in China.