基于边界变形的硅波导逆向三模式循环转换器

Inverse Triple-Mode Cyclic Converter of Silicon Waveguide Based on Boundary Deformation

摘要: 模式转换器是片上模分复用(MDM)系统的核心器件，其性能直接影响系统传输容量与集成密度。本文设计了一种基于绝缘体上硅(SOI)平台的逆向三模式循环转换器，实现了TE0-TE2、TE2-TE1、TE1-TE0的循环转换。采用边界变形逆向设计框架，核心创新在于引入两步差异化权重优化策略，实现各模式转换效率与串扰的均衡提升。仿真结果表明，器件功能区域尺寸仅7 μm × 1.65 μm，在1530~1570 nm波段内性能优异。1550 nm中心波长处传输效率模式纯度均高于97%，全波段非目标串扰低于−15 dB。工艺误差分析表明，在±10 nm尺寸偏差及局部随机误差下，器件性能波动小于0.8%，具备良好的工艺容差性。

Abstract: Mode converters are the core components of on-chip mode-division multiplexing (MDM) systems, and their performance directly affects the system’s transmission capacity and integration density. This paper presents the design of a reverse three-mode cyclic converter based on a silicon-on-insulator (SOI) platform, which enables cyclic conversion between TE0-TE2, TE2-TE1, and TE1-TE0. Using a boundary-deformation reverse-design framework, the core innovation lies in the introduction of a two-step differentiated weight optimization strategy, which achieves a balanced improvement in mode conversion efficiency and crosstalk. Simulation results show that the device’s functional area measures only 7 μm × 1.65 μm and exhibits excellent performance in the 1530~1570 nm wavelength band. At the center wavelength of 1550 nm, both transmission efficiency and mode purity exceed 97%, and off-target crosstalk across the entire wavelength band is below −15 dB. Process error analysis indicates that, under dimensional deviations of ±10 nm and local random errors, device performance variation is less than 0.8%, demonstrating good process tolerance.