We propose a joint look-up-table (LUT)-based nonlinear predistortion and digital resolution enhancement scheme to achieve high-speed and low-cost optical interconnects using low-resolution digital-to-analog converters (DACs). The LUT-based predistortion is employed to mitigate the pattern-dependent effect (PDE) of a semiconductor optical amplifier (SOA), while the digital resolution enhancer (DRE) is utilized to shape the quantization noise, lowering the requirement for the resolution of DAC. We experimentally demonstrate O-band intensity modulation and direct detection (IM/DD) transmission of 124-GBd 4 / 6-level pulse-amplitude modulation ( PAM ) -4 / 6 and 112-GBd PAM-8 signals over a 2-km standard single-mode fiber (SSMF) with 3 / 3.5 / 4-bit DACs. In the case of 40-km SSMF transmission with an SOA-based preamplifier, 124-GBd on-off-keying (OOK)/PAM-3/PAM-4 signals are successfully transmitted with 1.5 / 2 / 3-bit DACs. To the best of our knowledge, we have achieved the highest net data rates of 235.3-Gb / s PAM-4, 289.7-Gb / s PAM-6, and 294.7 Gb / s PAM-8 signals over 2-km SSMF, as well as 117.6-Gb / s OOK, 173.8-Gb / s PAM-3, and -231.8 Gb / s PAM-4 signals over 40-km SSMF, employing low-resolution DACs. The experimental results reveal that the joint LUT-based predistortion and DRE effectively mitigate the PDE and improve the signal-to-quantization noise ratio by shaping the noise. The proposed scheme can provide a powerful solution for low-cost IM/DD optical interconnects beyond 200 Gb / s.

Data centers, the engines of the global Internet, rely on powerful high-speed optical interconnects. In optical fiber communication, classic direct detection captures only the intensity of the optical field, while the coherent detection counterpart utilizes both phase and polarization diversities at the expense of requiring a narrow-linewidth and high-stability local oscillator (LO). Herein, we propose and demonstrate a four-dimensional Jones-space optical field recovery (4-D JSFR) scheme without an LO. The polarization-diverse full-field receiver structure captures information encoded in the intensity and phase of both polarizations, which can be subsequently extracted digitally. To our knowledge, our proposed receiver achieves the highest electrical spectral efficiency among existing direct detection systems and potentially provides similar electrical spectral efficiency as standard intradyne coherent detection systems. The fully recovered optical field extends the transmission distance beyond the limitations imposed by fiber chromatic dispersion. Moreover, the LO-free advantage makes 4-D JSFR suitable for photonic integration, offering a spectrally efficient and cost-effective solution for massively parallel data center interconnects. Our results may contribute to the ongoing developments in the theory of optical field recovery and the potential design considerations for future high-speed optical transceivers.

为丰富整层大气气溶胶光学厚度测量手段，提出了一种综合微脉冲激光雷达与地面能见度测量数据的探测方法。该方法首先利用激光雷达数据反演得到气溶胶垂直消光系数廓线，据此计算出气溶胶标高；再利用能见度和消光系数的关系得到近地面水平方向的消光系数；最后，将近地面消光系数和标高结合，从而得到整层大气气溶胶光学厚度。将该方法应用于合肥地区，成功得到该地区整层大气气溶胶光学厚度的昼夜变化趋势，验证了该方法的可适应性。

骨肉瘤是一种常见的恶性骨肿瘤, 常通过手术切除进行治疗。但术后造成的骨缺损难以自愈, 残余肿瘤细胞还会增加复发可能性。本研究开发了一种用于修复骨缺损和协同治疗骨肉瘤的掺钕介孔硼硅酸盐生物活性玻璃陶瓷骨水泥。首先通过溶胶-凝胶法结合固态反应制备了可作为光热剂和药物载体的掺钕介孔硼硅酸盐生物活性玻璃陶瓷微球(MBGC-xNd), 然后将微球与海藻酸钠(SA)溶液混合制备了可同时进行光热治疗和化学治疗的可注射骨水泥(MBGC-xNd/SA)。结果表明掺Nd³⁺赋予微球可控的光热性能, 负载阿霉素(DOX)的微球显示出持续的药物释放行为。此外, 载药骨水泥的药物释放量随着温度的升高而显著增加, 说明光热疗法产生的热量可促进DOX释放。体外细胞实验结果表明, MBGC-xNd/SA具有良好的促成骨活性, 并且光热-化学联合疗法对MG-63骨肉瘤细胞起到了更显著的杀伤作用, 表现出协同效应。因此，MBGC-xNd/SA作为一种新颖的多功能骨修复材料, 在骨肉瘤的术后治疗方面具有良好的应用前景。

K荧光辐射装置可填补国内超大型测量面积核辐射探测器计量检定需求, 该装置具通量高、 能量点多、 单色性好、 有成本低、 即开即用等优势。 其原理是X射线光机发射出的X射线轰击辐射体材料产生多种特征X射线即荧光射线, 在荧光射线出射路径上加入次级过滤器吸收掉多余的射线以提高荧光纯度, 辐射体以及次级过滤器的材料厚度值与荧光产额、 纯度直接相关。 通过MC(Monte Carlo)程序计算荧光装置各项指标参数结果, 指导后期试验装置的建立和研究, MCNP5(Monte Carlo N Particle Transport Code)软件模拟Cs₂SO₄辐射体数据表明: 荧光装置具有良好的屏蔽和准直的效果, 荧光以辐射体中心垂直面呈对称逐渐减小分布; 荧光产额随着辐射体厚度的增加逐渐增大, 但存在相对饱和厚度值, 即辐射体达到一定厚度值以后, 荧光产额不再随辐射体厚度的增加而增大, 而是趋于饱和状态; 为获取单一能量荧光辐射场, 在荧光出射束方向增加次级过滤器TeO₂材料, 其吸收L, K_β射线会远远大于K_α射线, 以达到消除L, K_β射线保留K_α射线目的, 形成单能的参考辐射场; 在距离辐射体中心30 cm处, 通过多组数据表明, 次级过滤厚度为0.035 cm时, 荧光纯度94.521%为最大且荧光产额最高; 荧光纯度随着次级过滤器材料的厚度增加呈现先增加后逐渐减小的趋势; 使用LEHGe探测器实际测量获取K荧光辐射装置能谱数据, 通过ROOT程序对测量能谱数据处理和分析, 拟合出K_α1和K_α2能量点的峰位道址误差小于0.005%, 测量分析出其能量值与理论值偏差分别为0.19%, 0.23%, 测量结果与实际理论能量值相符。 测量结果可验证MCNP5程序计算出的次级过滤器材料具有良好吸收效果且实现了单能荧光参考辐射场。