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无源-有源光电子混合集成芯片

在PLC无源芯片方面,承担了国家重点研发项目“无源光电子材料与器件研究”和河南省重大引领专项“高速数据中心光互连芯片研发及产业化”,开展了石英基、硅基二氧化硅AWG芯片关键技术研究,研制出4通道、O波段CWDM、LAN AWG芯片,解决了小尺寸、平坦宽带响应设计及工艺中互溶回流退火关键问题,通过了英特尔、索尔思及AOI等认证。

如图1所示为一个N×N的AWG结构示意图,其由N条输入波导,N条输出波导,两个聚焦平板波导(自由传播区)和阵列波导等五个部分组成。输入输出波导的位置和阵列波导的位置均满足罗兰圆原理,即各输入/输出波导连接自由传播区的一端以一定的中心间距Δx均匀地排列在一个罗兰圆圆周上,阵列波导连接自由传播区的一端则以一定的中心间距d分布在光栅圆圆周上。光栅圆的半径为R,也称为自由传播区的聚焦半径。罗兰圆起到凹面光栅的聚焦功能的作用,阵列波导的中心位于光栅圆与罗兰圆的切点处,相邻阵列波导保持特定的长度差ΔL。

AWG结构具有波分复用和解复用功能,以波分解复用功能为例,说明AWG的工作原理:复用光波耦合进入AWG的输入波导,在平板波导内衍射,并耦合进阵列波导区,因阵列波导端面位于光栅圆周上,所以衍射光以相同相位到达阵列波导端面,相同相位的衍射光,经长度差为L的阵列波导传输后,产生了相位差(不同波长的相位差也不同),于是,不同波长的光波被输出平板波导聚焦到不同的输出波导位置,即完成了解复用功能;如果光逆向输入,则实现复用功能,即合波功能,原理相同。AWG是无源合波器最常用的结构,本研究的无源合波器均采用AWG结构。

下面从AWG满足的光栅方程来分析其波分(解)复用功能。根据多光束干涉原理,AWG的光栅方程为:

Researchers employed the CTDE in two scenarios, predictions with baseline dataset and predictions with longitudinal dataset, to predict the scores with the dataset obtained from ADNI (Alzheimer’s disease Neuroimaging Initiative) database. 

The results demonstrated that the combination of correntropy regularized joint learning and DPN promoted the advantages of each other in the sense of increasing the prediction accuracy and discovering AD biomarkers. 

The comparisons experiment between the CTDE and state-of-the-art methods showed that the proposed CTDE model achieved the best performance. 

"One key advantage of our framework is that we utilized all the previous time points dataset to obtain the predicted scores at the next time point, which can improve the score prediction’s accuracy,” said Prof. WANG Shuqiang, “but still, other relevant clinical details, such as gender, education level and physiological factors of AD were not taken into account in this experiments. For further improving the clinical scores prediction performance, we will try to conduct more sophisticated feature selection and encoding methods in the next step.” 

The study has published in Pattern Recognition.