Abstract：
Monolithic integrated mode converters with high integration are essential to photonic integrated circuits (PICs), and they are widely used in next-generation optical communications and complex quantum systems. It is expected that PICs will become more miniaturized, multifunctional, and intelligent with the development of micro/nano-technology. The increase in design space makes it difficult to realize high-performance device design based on traditional parameter sweeping or heuristic design, especially in the optimal design of reconfigurable PIC devices. Combining the mode coupling theory and adjoint calculation method, we proposed a design method for a switchable mode converter. The device could realize the transmission of TE0 mode and the conversion from TE0 to TE1 mode with a footprint of 0.9 × 7.5 μm2 based on the phase change materials (PCMs). We also found that the mode purity could reach 78.2% in both states at the working wavelength of 1.55 μm. The designed method will provide a new impetus for programmable photonic integrated devices and find broad application prospects in communication, optical neural networks, and sensing.
摘要：
具有高集成度的单片集成模式转换器对于光子集成电路（PIC）至关重要，广泛应用于下一代光通信和复杂的量子系统。预计PIC将变得更加小型化，多功能,随着微纳米技术的发展和智能化。设计空间的增加使得基于传统参数扫描或启发式设计的高性能器件设计难以实现,特别是在可重构PIC器件的优化设计中。结合模式耦合理论和伴随计算方法，提出了一种可切换模式变换器的设计方法。基于相变材料（PCM），该器件可以实现TE0模式的传输以及从TE0到TE1模式的转换，占用面积为0.9×7.5μm2。我们还发现，在1.55μm的工作波长下，两种状态下的模式纯度都可以达到78.2％。所设计的方法将为可编程光子集成器件提供新的动力,并在通信领域找到广阔的应用前景,光学神经网络，和感应。
