Excitons have significant impacts on the properties of semiconductors. They exhibit significantly different properties when a direct semiconductor turns in to an indirect one by doping. Huybrecht variational method is also found to influence the study of exciton ground state energy and ground state binding energy in Al_xGa_1?xAs semiconductor spherical quantum dots. The Al_xGa_1?xAs is considered to be a direct semiconductor at Al concentration below 0.45, and an indirect one at the concentration above 0.45. With regards to the former, the ground state binding energy increases and decreases with Al concentration and eigenfrequency, respectively; however, while the ground state energy increases with Al concentration, it is marginally influenced by eigenfrequency. On the other hand, considering the latter, while the ground state binding energy increases with Al concentration, it decreases with eigenfrequency; nevertheless, the ground state energy increases both with Al concentration and eigenfrequency. Hence, for the better practical performance of the semiconductors, the properties of the excitons are suggested to vary by adjusting Al concentration and eigenfrequency

A new theoretical method to study super-multiperiod superlattices has been developed. The method combines the precision of the 8-band kp-method with the flexibility of the shooting method and the Monte Carlo approach. This method was applied to examine the finest quality samples of super-multiperiod Al_0.3Ga_0.7As/GaAs superlattices grown by molecular beam epitaxy. The express photoreflectance spectroscopy method was utilized to validate the proposed theoretical method. For the first time, the accurate theoretical analysis of the energy band diagram of super-multiperiod superlattices with experimental verification has been conducted. The proposed approach highly accurately determines transition peak positions and enables the calculation of the energy band diagram, transition energies, relaxation rates, and gain estimation. It has achieved a remarkably low 5% error compared to the commonly used method, which typically results in a 25% error, and allowed to recover the superlattice parameters. The retrieved intrinsic parameters of the samples aligned with XRD data and growth parameters. The proposed method also accurately predicted the escape of the second energy level for quantum well thicknesses less than 5 nm, as was observed in photoreflectance experiments. The new designs of THz light-emitting devices operating at room temperature were suggested by the developed method.

This paper experimentally demonstrates a distributed photonics-based W-band integrated sensing and communication (ISAC) system, in which radar sensing can aid the communication links in alignment and data rate estimation. As a proof-of-concept, the ISAC system locates the users, guides the alignment, and sets a communication link with the estimated highest data rate. A peak net data rate of 68.6 Gbit/s and a target sensing with a less-than-1-cm error and a sub-2-cm resolution have been tested over a 10-km fiber and a 1.15-m free space transmission in the photonics-based W-band ISAC system. The achievable net data rates of the users at different locations estimated by sensing are experimentally verified.

针对现有多波段成像系统体积大、功耗高和集成化设计困难的问题，本文提出了一种基于单传感器的三波段共口径成像光学系统的设计方法。首先，在光学系统的光阑处设计1×2多波段透镜阵列，把可见光波段和短波红外波段同时成像在一个像平面上，并把两个波段中心波长的成像位置偏差控制在一个像元内以实现双波段融合成像。然后，针对双波段成像衍射极限不同的问题，提出分通道透镜阵列的离轴偏移量和通光口径大小联合优化方法，并采用双电动光阑高速控制三个成像通道的切换速度。最后，设计了一个基于单传感器的焦距为30 mm，工作波段分别为480~900 nm、900~1700 nm和480~1700 nm的三波段共口径光学系统。设计及分析结果表明该系统具有成像质量好、结构紧凑、无运动光学元件、成像波段切换速度快等优点。

光学频率梳（简称光频梳）作为一种优秀的多波长光源在通信领域具有巨大的应用潜力。通过将光频梳光源与波分复用技术（WDM）、空分复用技术结合（SDM），通信系统可以具有百Tbit/s量级的传输速率，在5G/6G通信、物联网、自动驾驶等方面具有重要的应用价值。目前实现光频梳的方法主要有以下四种，分别为基于锁模激光器产生飞秒光频梳、基于光学微腔产生光频梳、基于电光调制器产生光频梳以及基于行波四波混频产生光频梳。它们各具特点，但均很难同时实现宽光谱、高信噪比、高平坦度、高的单梳齿功率以及梳齿频率间隔大范围可调，这在一定程度上影响了光频梳在光通信领域的应用。本文提出基于受激布里渊激光腔产生种子梳，采用腔外负色散光纤进行脉冲压缩，进一步利用色散调控的高非线性氟碲酸盐光纤进行扩谱，从而实现光频梳产生。数值计算结果表明，通过该系统，我们可以得到重复频率大范围可调、光谱覆盖整个O-U波段且在O-U波段梳齿强度标准差小于5 dB的平坦光频梳，证明了通过基于布里渊激光腔与色散调控高非线性氟碲酸盐光纤的光学系统产生可用于光通信的平坦光频梳的可行性。

针对现有光纤无法满足宽带光密集波分复用系统传输和S+C+L波段粗波分复用的要求，设计了一种具有中心凹陷的三角形芯+环形的折射率剖面，利用外部气相沉积工艺制备了一种非零色散位移光纤，并通过调整第一芯层的相对折射率和第二芯层与第一芯层的半径比，探究了其对光纤衰减、色散斜率和有效面积等参数的影响。研究发现，当第一芯层的相对折射率逐渐增大且第二芯层与第一芯层半径比逐渐减小时，零色散波长和有效面积逐渐减小。当第一芯层的相对折射率在0.52%~0.53%，芯层半径比在2.6~2.7时，光纤的有效面积接近70 μm²，零色散波长在1 420 nm附近，在1 550 nm波段的色散系数大于8 ps·nm^-1·km^-1，色散斜率为0.059 ps·nm^-2·km^-1，可以较好地抑制传输过程中光非线性效应，满足长途干线网与城域网的使用要求。