基于启发式遗传算法求解加工时间可控单台机器

对NP—Hard的加工时间可控单机排序问题提出一种启发式遗传算法求解其次优解。在介绍该问题数学模型后,利用二维编码描述加工次序与加工时间,染色体的第一行用整数编码来表示工件加工次序,染色体第二行用实数编码表示实际加工时间。根据启发式知识定义了新的交叉与变异操作,这样不仅容易产生优良的初始解,而且缩小了搜索范围,提高了搜索速度和精度。算例仿真研究验证了提出算法的有效性。     

Optical total reflection and transmission with mode control in a dielectric subwavelength nanorod chain

We report a polarization dependent reflection phenomenon beyond the normal incidence with a subwavelength nanorod chain.Light waves of the transverse electric mode will be totally reflected while those of the transverse magnetic mode will transmit through.The total reflection or transmission phenomenon can be seen as a constructive or destructive interference of the incident field with the transverse mode field of the chain.With the low-loss feature and the ultra-compact characteristic,this structure may find applications in photonic circuits.     

High efficiency grating couplers based on shared process with CMOS MOSFETs

Grating couplers are widely investigated as coupling interfaces between silicon-on-insulator waveguides and optical fibers.In this work,a high-efficiency and complementary metal-oxide-semiconductor(CMOS) process compatible grating coupler is proposed.The poly-Si layer used as a gate in the CMOS metal-oxide-semiconductor field effect transistor(MOSFET) is combined with a normal fully etched grating coupler,which greatly enhances its coupling efficiency.With optimal structure parameters,a coupling efficiency can reach as high as ～ 70% at a wavelength of 1550 nm as indicated by simulation.From the angle of fabrication,all masks and etching steps are shared between MOSFETs and grating couplers,thereby making the high performance grating couplers easily integrated with CMOS circuits.Fabrication errors such as alignment shift are also simulated,showing that the device is quite tolerant in fabrication.     

硅基片上刻蚀衍射光栅及其平坦化设计

刻蚀衍射光栅（EDG）作为实现波分复用功能的关键器件,对于片上光互连的实现至关重要。为了实现1310nm波段通道间隔为20nm的硅基EDG,采用了基尔霍夫标量衍射理论仿真方法进行理论设计和仿真验证,通过在闪耀光栅反射面引入布喇格反射光栅来提高反射效率、降低器件插入损耗,并在入射波导处引入多模干涉耦合器以实现通道频谱平坦化设计。结果表明,闪耀光栅反射面的反射效率由35%提高到了85%,1dB带宽达到12nm。这对于提高系统稳定性、增大传输距离和容量、降低系统成本具有显著作用,能够满足光互连系统的实际应用需求。     

CMOS兼容的中红外多通道光子晶体传感器

我们提出了一种基于光子晶体的二维多通道光学化学传感器。该器件由中心波长为3.3 μm的四个腔组成,各通道工作波长间隔为10 nm。该传感器采用800 nm厚的绝缘体上硅材料,可利用标准CMOS技术加工。我们通过三维时差有限差分法对微腔结构的光学特性进行模拟。每个通道的传输效率为39％,通道之间的传输效率不一致性小于0.25dB。该传感器的功能为检测四氯化碳和苯溶液浓度,其灵敏度为209.2 nm/RIU。     

基于联盟链的运营商最佳缓存策略

基于区块链的边缘缓存技术可以实现更大范围的内容共享并提高缓存内容的使用效率。针对不同运营商各自建设边缘设备,缓存内容相互隔离,难以共享信息的问题,该文提出一种基于联盟链的边缘缓存系统框架并设计了内容共享和交易流程,实现了不同运营商之间的内容共享。此外,为了降低高维缓存节点的共识开销,设计了基于内容缓存的部分实用拜占庭容错(pPBFT)共识机制,仅选取缓存相关内容的联盟链节点作为验证智能合约的执行节点。最后,将运营商内容共享所带来的收益进行量化并构建为最大化收益的优化问题。通过所提出的内容缓存算法,得到了最优缓存决策的闭式表达式和与内容流行度相关的最优缓存策略。仿真结果表明,在该框架中所提出的共识机制和缓存策略能够有效增加运营商的缓存收益。