Chip发表：基于三维波导的片上差分模式群延迟操控

游戏天地 2025年08月31日 05:38 1 admin

近日，广东工业大学秦玉文团队以「On-chip differential mode group delay manipulation based on 3D waveguides」¹为题在Chip上发表研究论文，利用在纤芯与包层之间引入低折射率差材料作为内包层，实现约为10 ps/m@1550 nm的差分模式群时延调控功能。第一作者为刘晓锋，通讯作者为黄权东副教授。

模式分复用（MDM）技术是提高光纤通信系统传输容量的关键技术之一2。然而，在少模光纤中，不同模式的群速度差异会导致模式差分群延迟（DMGD）3，增加多输入多输出数字信号处理（MIMO-DSP）的复杂度，从而限制系统性能。传统的光纤补偿方法难以实现高集成化，因此在本工作中，研究者开发了基于光子芯片的DMGD调控器件（图1）。

图1 | DMGD操控器件的概念和结构。

研究学者通过在纤芯与包层之间引入低折射率差材料作为内包层，设计DMGD控制的多层波导（图2a）。研究多层波导的特性（图2b），得到约为10 ps/m（1550 nm）的DMGD调控功能（图2c）。调整波导芯层与内包层的尺寸，实现对DMGD的精确控制（图2c，d，f）。

图2 | 器件对DMGD的调控。(a) 器件横截面；(b) E11和E21模式的透射光谱及传播常数差随波长变化曲线（其中λ1为临界波长）；(c) DMGD随波长变化曲线，λ2为E21模式截止波长；(d) 芯层与内包层宽度差与高度差变化时，DMGD随波长的变化曲线；(e) λ1、λ2随芯层宽度（w1）和高度（h1）的变化关系；(f) λ1、λ2随内包层宽度（w2）和高度（h2）的变化关系。

采用聚合物材料，通过微纳加工技术（图3a）制备器件，并记录了制备期间器件（图3b,c,d,e）并通过光学测试平台（图3f）得到近场模式和传输谱（图3g）。实验测得的器件临界波长λ1与仿真结果吻合，且对偏振不敏感。

图3 | 器件制备与测试。(a) 器件的制备工艺; (b) 器件样品的俯视图; (c) 螺旋波导间隙; (d) 内包层与 (e) 波导芯层; (f) 用于测量器件近场模式及透射光谱的实验装置; (g) 实验与仿真器件的透射光谱对比。

该研究提出了一种基于3D波导的片上DMGD调控方案，通过低/高折射率差材料实现了从10 ps/m到ns/m量级的时延调控。引入高折射率材料的进一步提升了器件的集成度和动态调控能力，为未来MDM系统的片上集成提供了关键技术支撑。

On-chip differential mode group delay manipulation based on 3D waveguides¹

Mode Division Multiplexing (MDM) technology stands as a cornerstone for enhancing transmission capacity in fiber-optic communication systems. However, in few-mode fibers, the group velocity differences between modes can induce differential mode group delays (DMGD), which increases the complexity of Multiple-Input Multiple-Output Digital Signal Processing (MIMO-DSP) and consequently limits system performance. Conventional fiber compensation methods struggle to achieve high integration. To address this, researchers have developed a photonic chip-based DMGD control device (Fig. 1) in this study.

Researchers designed a DMGD-controlled multilayer waveguide by incorporating a low refractive index difference material as an inner cladding between the core and cladding (Fig. 2a). Characteristic measurements of the multilayer waveguide (Fig. 2b) revealed precise DMGD control functionality at approximately 10 ps/m (1550 nm) (Fig. 2c). Through dimensional adjustments of the waveguide's core and inner cladding, researchers achieved precise control over the DMGD characteristics (Fig. 2c, 2d, 2f).

The device was fabricated using polymer materials through micro/nano processing technology (Fig. 3a). The fabricated devices (Fig. 3b, 3c, 3d, 3e) were recorded during the preparation process, and near-field patterns and transmission spectra were obtained through an optical testing platform (Fig. 3f) via Fig. 3g. Experimental measurements of the device's critical wavelength λ1 showed good agreement with simulation results, demonstrating polarization insensitivity.

This study proposes a 3D waveguide-based on-chip DMGD control scheme, achieving delay regulation from 10 ps/m to ns/m through low/high refractive index difference materials. The introduction of high refractive index materials further enhances the device's integration density and dynamic control capabilities, providing crucial technical support for future on-chip integration of MDM systems.

参考文献

1. Liu, X. Huang, Q. et al. On-chip differential mode group delay manipulation based on 3D waveguides. Chip 4, 100137 (2025).

2. Puttnam, B. J., Rademacher, G. & Luís, R. S. Space-division multiplexing for optical fiber communications. Optica 8, 1186e1203 (2021).

3. Shibahara, K. et al. Advanced MIMO signal processing techniques enabling long-haul dense SDM transmissions. J. Light. Technol. 36, 336e348 (2018).

论文链接：

https://www.sciencedirect.com/science/article/pii/S2709472325000115