Author Affiliations
Abstract
1 School of Electronic Information and Communications, Huazhong University of Science and Technology, Wuhan 430074, China
2 Wuhan National Laboratory for Optoelectronics and School of Optical and Electronic Information, Huazhong University of Science and Technology, Wuhan 430074, China
In this paper, an integrated compact four-channel directly modulated analog optical transceiver is proposed and fabricated. The 3 dB bandwidth of this optical transceiver exceeds 20 GHz, and the measured spurious-free dynamic range is up to . The optical coupling efficiency (CE) is improved by using a precise submicron alignment technique for lens coupling in a transmitter optical subassembly, and the highest CE is achieved when the oblique angle of the arrayed waveguide grating using a silica-based planar lightwave circuit (AWG-PLC) in receiver optical sub assembly is set to 42°. Based on the proposed optical transceiver, we have experimentally demonstrated a 6.624 Gbit/s multi-input multioutput (MIMO) 16-quadrature amplitude modulation orthogonal frequency division multiplexing (16QAM-OFDM) radio signal over 15.5 km standard single mode fiber, together with 1.2 m wireless transmission in both an uplink and a downlink. To cope with the channel interference and noise of the fiber-wireless transmission system, a low-complexity MIMO demodulation algorithm based on lattice reduction zero-forcing (LR-ZF) is designed. In our experiment, 1.6 dB power penalty is achieved by using the proposed LR-ZF algorithm, compared to the commonly used zero-forcing algorithm. Moreover, this LR-ZF algorithm has much less complexity than the optimal maximum-likelihood sequence estimation (MLSE) at a given transmission performance. These results not only demonstrate the feasibility of the integrated optical transceiver for MIMO fiber-wireless application but also validate that the proposed LR-ZF algorithm is effective to eliminate the interference for hybrid fiber-wireless transmission.
Photonics Research
2019, 7(12): 12001461
1 合肥鑫晟光电科技有限公司, 安徽 合肥 230012
2 群龙企业咨询(上海)有限公司, 上海 200335
3 合肥乐凯科技产业有限公司, 安徽 合肥 230041
Particle Gap是TFT-LCD制程中常见的一种缺陷。以55 UHD产品为例, Particle Gap发生率约为1.0%, 对产品良率影响较大, 为提升液晶屏品质和客户满意度, 急需改善此不良。文章结合不良现象研究Particle Gap的主要异物模式, 最终通过改善CF研磨失败异物、沙粒状异物和透明状异物这种模式达到整体Particle Gap降低的效果。首先利用流程图分析影响异物模式的关键步骤, 然后通过鱼骨图、决策矩阵、假设检验验证找出影响异物模式的显著因素, 最后通过合力促进法总结出显著因素的最佳改善方案, 导入量产并文件标准化, 可平行推广至55UHD以外的其它尺寸。改善结果表明：通过以上3种异物类型的改善, 55UHD Particle Gap发生率降低至少30%, 为公司带来了巨大且显著的硬性节省。
薄膜电晶体-液晶显示器 CF研磨失败异物 透明状异物 沙粒状异物 TFT-LCD Particle gap Particle Gap CF grinding failure particle transparent particle sandy particle
1 中国科学院长春光学精密机械与物理研究所, 吉林 长春 130033
2 中国科学院大学, 北京 100049
3 长光卫星技术有限公司, 吉林 长春 130033
针对吉林一号视频03星凝视成像的特点,为提高其图像空间分辨率,解决光学系统分辨率不足的问题,提出一种视频卫星超分辨率重建的新算法--凸集中间映射。以主动观点分析视频卫星凝视成像特点,建立了基于凝视成像的图像降质模型。为求解该降质模型的逆过程,以凸集理论为基础,建立了基于中间降质过程的约束集和相应的点投影算子,通过点投影算子逐帧修正高分辨率图像灰度值,最终将重建的高分辨率图像约束于凸集的交集上。实验结果表明,该算法使图像分辨率提高近30%,克服了同类算法具有投影误差和重叠伪影的缺点,图像质量评价指标均优于所列其他算法,8帧重建得到收敛解,对不同清晰度的图像重建均具有可行性和稳健性。说明该算法适用于视频卫星图像超分辨率重建。
图像处理 超分辨率重建 凝视成像降质模型 凸集中间映射 点投影修正
