Equivalent Photoconductive Time-Domain Sampling for Monitoring High-Speed Terahertz Communication Signals
Journal of Lightwave Technology 2024
Hongqi Zhang, Lu Zhang, Zuomin Yang, Zhidong Lyu, Hang Yang, Changming Zhang, Vjačeslavs Bobrovs, Oskars Ozoliņš, Xiaodan Pang, Xianbin Yu

Over the past few years, numerous photonic-wireless transmission demonstrations with high data rates in the terahertz (THz) band have been reported, aiming to supporting the explosive growth of data traffic in next-generation communication networks. Usually, real-time analysis of THz signals is implemented in the intermediate frequency domain by using electronic down-converters with limited bandwidth, which brings inconvenience to the monitoring of very large THz bandwidth. In this work, an equivalent-time sampling (ETS) system based on a conventional photoconductive antenna (PCA) for capturing and monitoring high-speed THz signals is proposed, theoretically analyzed, and experimentally demonstrated. The PCA, excited by optical pulses from a mode-locked laser (∼100 MHz) and biased by the THz fields, enables the equivalent optical sampling of THz signals into low-frequency regions. In our proof-of-concept experiment, a single-frequency signal at 125 GHz and 16-ary quadrature amplitude modulation (16-QAM) signals at a baud rate of 15 Gbaud at 125 GHz are successfully sampled, monitored, and evaluated with a ∼100 MHz sampling rate. In this way, the high-speed THz signals can be easily accessible with no need of additional high-frequency components. The waveform distortion values for single-frequency and high-speed communication signal are 0.11%, 2.96% (in-phase) and 2.56% (quadrature). Our proposed ETS system is expected to provide a simple, convenient, and straightforward approach to capture and monitor broadband THz signals.


Keywords
Antennas; Frequency domain analysis; Laser pulses; Locks (fasteners); Mode-locked fiber lasers; Photoconductivity; Principal component analysis; Quality control; Signal analysis; Signal sampling; Terahertz waves; Time domain analysis
DOI
10.1109/JLT.2024.3372382
Hyperlink
https://ieeexplore.ieee.org/document/10457540

Zhang, H., Zhang, L., Yang, Z., Lyu, Z., Yang, H., Zhang, C., Bobrovs, V., Ozoliņš, O., Pang, X., Yu, X. Equivalent Photoconductive Time-Domain Sampling for Monitoring High-Speed Terahertz Communication Signals. Journal of Lightwave Technology, 2024, Vol. 42, No. 13, pp.4476-4484. ISSN 0733-8724. e-ISSN 1558-2213. Available from: doi:10.1109/JLT.2024.3372382

Publication language
English (en)
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