Multimode-enabled silicon photonic delay lines: break the delay-density limit

Shihan Hong; Long Zhang; Jiachen Wu; Yingying Peng; Linyan Lyu; Yinpeng Hu; Yiwei Xie; Daoxin Dai

doi:10.1038/s41377-025-01820-2

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Multimode-enabled silicon photonic delay lines: break the delay-density limit

Original Articles

- Multimode-enabled silicon photonic delay lines: break the delay-density limit
- Light: Science & Applications Vol. 14, Issue 6, Pages: 1532-1540(2025)
- Affiliations：
  
  1.State Key Laboratory for Extreme Photonics and Instrumentation, College of Optical Science and Engineering, International Research Center for Advanced Photonics, Zhejiang University, Zijingang Campus, Hangzhou 310058, China
  2.Intelligent Optics and Photonics Research Center, Jiaxing Research Institute, Zhejiang University, Jiaxing 314000, China
  3.Ningbo Research Institute, Zhejiang University, Ningbo 315100, China
- Author bio：
  
  Daoxin Dai (dxdai@zju.edu.cn)
- Funds：
- DOI：10.1038/s41377-025-01820-2
  CLC：
- Received：10 August 2024，
  
  Revised：05 March 2025，
  
  Accepted：09 March 2025，
  
  Published Online：31 March 2025，
  
  Published：30 June 2025
- Accepted：
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Hong, S. H. et al. Multimode-enabled silicon photonic delay lines: break the delay-density limit. Light: Science & Applications, 14, 1532-1540 (2025).
DOI：

Hong, S. H. et al. Multimode-enabled silicon photonic delay lines: break the delay-density limit. Light: Science & Applications, 14, 1532-1540 (2025). DOI： 10.1038/s41377-025-01820-2.

摘要

Abstract

Integrated optical delay lines have become imperative to meet the growing demand as large aperture antennas and high number of subarrays required for microwave beamforming

high-speed optical communication

and integrated quantum photonics. It is very challenging to achieve large delay ranges

small footprints

and broad bandwidths simultaneously due to the strong trade-off between the propagation loss and the group refractive index of optical waveguides. In this paper

we propose and experimentally demonstrate multimode-enabled silicon photonic delay line for

the first time

which breaks the delay-density limit of singlemode waveguide spirals

towards a broadband

-scale

and ultra-large time delay. By demonstrating low-loss-propagation possibilities for different polarizations and modes

we introduce a novel multimode delay unit by integrating the mode (de)multiplexers and the ultralow-loss multimode waveguide spiral supporting the TE

and TE

modes propagating in parallel. The measured propagation losses for the TE

and TE

modes are 0.2 dB/cm

0.31 dB/cm

and 0.49 dB/cm

respectively. In this way

the

highest

line delay-density of 376.9 ps/cm and low delay loss of 0.004 dB/ps are achieved. Furthermore

we implement a 7-bit tunable multimode photonic delay line and experimentally demonstrate an ultra-large delay range of 12.7 ns with a delay resolution of 100 ps and within an ultra-compact footprint of 3.85 mm

enabling a delay density over 3299 ps/mm

showing the

largest

delay range and the

highest

delay density among on-chip delay lines reported to date

to the best of our knowledge.

关键词

Keywords

references

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