Single-shot optical transfer delay measurement with sub-picosecond accuracy and sub-millisecond range

作者：Lihan Wang, Xiangchuan Wang, Xijun Liu, Yue Yang, Shupeng Li, Sihao Yang, Qianwen Sang, Zhijian Zhang, Jingxian Wang, Shilong Pan · 发表于：Photonics Research · 年份：2025 · DOI：10.1364/prj.536776 · 被引用次数：5 · 研究领域：Photonic and Optical Devices、Advanced Photonic Communication Systems、Optical Coherence Tomography Applications

Optical transfer delay (OTD) is essential for distributed coherent systems, optically controlled phased arrays, fiber sensing systems, and quantum communication systems. However, existing OTD measurement techniques typically involve trade-offs among accuracy, range, and speed, limiting the application in the fields. Herein, we propose a single-shot OTD measurement approach that simultaneously achieves high-accuracy, long-range, and high-speed measurement. A microwave photonic phase-derived ranging with a nonlinear interval microwave frequency comb (MFC) and a discrete frequency sampling technique is proposed to conserve both frequency and time resources, ensuring high-accuracy and ambiguity-free measurements. In the proof-of-concept experiment, a delay measurement uncertainty at the 10 −9 level with a single 10 μs sampling time is first reported, to our knowledge. The method is also applied to coherently combine two distributed signals at 31.8 GHz, separated by a 2 km optical fiber. A minimal gain loss of less than 0.0038 dB compared to the theoretical value was achieved, corresponding to an OTD synchronization accuracy of 0.3 ps.