Yuan Jiaqi, Wang Yanwei, Han Zhe, Qi Yan, Yan Boxia, Fan Yuanyuan, Zhou Mi, Wang Qian
Appl Opt. 2025 Mar 20;64(9):2269-2275. doi: 10.1364/AO.555092.
Mode converters play a critical role in mode-division multiplexing (MDM) systems. This paper proposed and demonstrated a design method of high conversion efficiency (CE) and broadband mode converters based on cubic spline interpolation curves. The cubic spline interpolation method provides great flexibility in defining the boundaries of irregularly shaped waveguide curves. This design effectively improves the mode conversion efficiency and can be applied to different mode orders and multimode waveguide widths. For the TE0-TE1 converters, we designed different multimode waveguide widths (1 µm and 1.1 µm) to demonstrate the flexibility of the design approach. At 1550 nm, the conversion efficiencies of the TE0-TE1 converters and TE0-TE2 converters are -0.026 (99.4%) and -0.039 (99.1%), respectively, according to the theoretical results. The mode converters were manufactured using a standard process provided by the foundry, and the measured conversion efficiency for all devices was above -0.419 (90.8%) in the wavelength range of 1530-1565 nm.
模式转换器在模式分割复用（MDM）系统中起着关键作用。本文提出并演示了一种基于三次样条插值曲线的高转换效率（CE）和宽带模式转换器的设计方法。三次样条插值方法在定义不规则形状波导曲线的边界方面提供了极大的灵活性。这种设计有效地提高了模式转换效率，并且可以应用于不同的模式阶次和多模波导宽度。对于TE0-TE1转换器，我们设计了不同的多模波导宽度（1 µm和1.1 µm）以展示该设计方法的灵活性。根据理论结果，在1550 nm处，TE0-TE1转换器和TE0-TE2转换器的转换效率分别为-0.026（99.4%）和-0.039（99.1%）。这些模式转换器是使用代工厂提供的标准工艺制造的，在1530-1565 nm波长范围内，所有器件的实测转换效率均高于-0.419（90.8%）。
