中心博士研究生沈碧涛在集成模分复用器设计方面相关工作发表在了SCIENCE CHINA Information Sciences期刊的AI-Photonics专题中。该工作得到了国家自然科学基金(61635001, 61822508)，国家自然科学基金国际合作与交流项目(61120106012)，北京市科委项目(Z19110004819006)的部分资助。

宽度渐变的非对称定向耦合器可实现高工艺容差的片上模分复用器，然而关于渐变区域的参数优化一直没有系统的设计方案。本文提出一种基于调整的耦合模理论与遗传算法的片上模分复用器设计方法，与基于三维仿真参数扫描的设计方法相比，这种方法极大地降低了优化设计的时间开销。

摘要:The tapered asymmetric directional coupler has the potential to realize high fabrication tolerance and high transmission efficiency on-chip mode multiplexer. However, the geometry parameter selection of tapered structure remains empirical. In this paper, we propose a design method for the tapered structure based on genetic algorithm. Combined with the adjusted coupling equations and interpolation method, low-time-cost optimization can be realized. Three mode multiplexers (TE0&TE1, TE0&TE2 and TE0&TE5) are designed by our method. According to simulation results, the insertion loss of the designed devices is lower than 1.8 dB and the crosstalk is lower than −15 dB when the fabrication error is within required range (±10 nm for TE0&TE2 and TE0&TE5, and ±20 nm for TE0&TE1) in the bandwidth of 1.5–1.6 µm. In addition, the entire optimization process takes only 2 h for each device, which is around the time cost of a single 3D simulation.

论文链接：

Bitao Shen, Haowen Shu, Linjie Zhou, Xingjun Wang "A design method for high fabrication tolerance integrated optical mode multiplexer." SCIENCE CHINA Information Sciences. 63, 160409 (2020)