【摘 要】
：
Visible light communication based on light-emitting diodes (LEDs) has become a promising candidate by providing high data rates, low latency, and secure communication for underwater environments. In this paper, a self-designed common-anode GaN-based five-
【机 构】
：
DepartmentofCommunicationScienceandEngineering,KeyLaboratoryforInformationScienceofElectromagneticWa
【出 处】
：
PhotonicsResearch
论文部分内容阅读
Visible light communication based on light-emitting diodes (LEDs) has become a promising candidate by providing high data rates, low latency, and secure communication for underwater environments. In this paper, a self-designed common-anode GaN-based five-primary-color LED (RGBYC LED) on a Si substrate is proposed and fabricated. The design of a common anode is used to mitigate the saturation effect for a low-frequency component. Additionally, compared with commercially available LEDs that suffer from nonlinearity distortion, applying the designed LED can provide much better and broader linearity according to the measurement results. Therefore, the modulation depth and system performance can be further improved to implement a high-speed underwater visible light communication (UVLC) system. There is no nonlinearity compensation algorithm applied due to the good linearity of the proposed LED; thus, the offline digital signal processing is simplified. We experimentally demonstrate 14.81 Gbit/s 64 quadrature amplitude modulation (QAM)-discrete multitone (DMT) and 15.17 Gbit/s bit-loading-DMT transmissions through a 1.2-m-long underwater channel based on the proposed RGBYC LED with an intrasymbol frequency-domain averaging channel estimation and zero-forcing equalization. As far as we know, this is the highest data rate for an LED-based UVLC system.
其他文献
本文报导用辐射功率为20瓦的连续CO2激光泵浦时，获得亚毫米波CH3OH分 子激光器在150~970微米波段的48条新振荡谱线，10条CH3NH2分子振荡新谱线,还获得CH3NHD和CH3NH2分子的9条振荡谱线。
美帝万国虫胶供应公司制成了一种新的激光抛光机商品。抛出的激光棒的表面的光学平整度在0.1个波长之内，两端面的平行度在2~4弧秒之内。在抛制球面半径时也能达到同样的公差。
In landmark-based image registration, estimating the landmark correspondence plays an important role. In this letter, a novel landmark correspondence estimation technique using mean shift algorithm is proposed. Image corner points are detected as landmark
成像仿真是相机研制必不可缺的步骤。航空线阵摆扫式相机具有距离远、成像倾角大的特点,容易导致成像仿真过程中坐标投影计算迭代不收敛。针对这一问题,提出一种视向量分段迭代的坐标投影计算方法。首先将迭代窗口内的视向量进行分段,根据像点坐标和其所在扫描行的外方位元素计算各分段处的高程与对应的地面点的高程之差,寻找差值最小的分段;然后在该分段处继续构建迭代窗口进行计算,直至高程差值的最小值小于给定的阈值,得到
采用微波水热法一步合成了核壳结构的CdSe/CdS纳米晶, 讨论了巯基丙酸中S2-的释放过程对纳米晶生长的影响。XRD和Raman光谱结果表明, 140 ℃合成温度下获得了CdSe/CdS核壳结构的纳米晶。FTIR光谱结果表明, 巯基丙酸随时间的分解有助于CdS壳层的形成。PL光谱呈现出CdSe纳米晶的带间发射和缺陷发射, 随着核壳结构的形成, CdSe纳米晶的表面缺陷被抑制, 相关的荧光发射减弱。
美国佐治亚理工学院研制出一种用激光诊断白内障的新技术。这种把激光通过水晶体时产生的散射光进行喇曼分光的方法不会给眼睛带来任何损伤,即便在白浊产生前,也能在分子水平上捕捉到白内障的进展。这种划时代的诊断法目前虽然还停留在动物实验阶段，但由于迄今为止早期发现白内障极为困难，故人们对它的付诸实用仍寄予很大希望。
考虑双模纠缠相干光场中,其中一束光场注入腔中与一个级联型三能级原子发生共振相互作用的情况。采用数值计算方法,研究了另一束腔外光场的压缩效应,反聚束效应以及描述双模场相关性的Cauchy-Schwartz不等式等量子特性的演化规律。讨论了采用选择原子测量方法和纠缠光中参与原子相互作用的光场的强度对另一束腔外光场量子特性的影响。研究结果表明,采用选择原子测量方法和选择参与相互作用的光场的强度,可导致未参加相互作用的光场量子特性的明显增强。
意大利CISE为检测米兰市甲烷分布网泄漏而设计的激光系统基于光雷达一差分吸收光雷达技术。它由发射频率与甲烷的高红外辐射吸收带一致的远红外激光源组成。
针对经典稳定控制理论存在超调与快速性之间难以调和的矛盾，建立了稳定控制系统数学模型，采用自适应模糊实现控制的快速性，用PI保证系统的稳态精度，以误差为模糊控制的输入，设计一种实用的自适应模糊和PI复合控制系统，并在基于VxWorks实时操作系统的数字平台上得以实现。仿真和试验表明：设计的新型自适应模糊PI复合控制系统超调量为0，调节时间约8ms，带宽约29Hz。