Recently, Prof. Dong Yongkang and his research team achieved a breakthrough in the field of microwave photonics frequency measurement. The results of this study were published in Laser & Photonics Reviews entitled "Real-time and high-accuracy microwave frequency identification based on ultra-wideband optical chirp chain transient SBS effect".
Microwave photonics frequency measurement implements by loading the microwave signal on the optical carrier through electro-optical modulation technology, converting and transmitting through optical means, and finally detecting the optical signal to demodulate the microwave frequency information, which therefore have emphasized potential advantages, such as broad bandwidth, reconfigurable, low loss and anti-electromagnetic interference. Real-time and high-accuracy measurement of microwave frequencies delivers clear time-frequency joint characteristics, providing a unique solution for detection and analysis of fast rare events in several field applications of 5G communication, internet of things, digital twin and biomedicine. However, most of the existing schemes hardly combine the high temporal resolution and high frequency accuracy, and hardly adapt to complex use environment.
This study innovatively proposes a real-time and high-accuracy microwave frequency measurement scheme. The scheme uses continuous light as a carrier to load the microwave signals, and samples the microwave frequency in temporal domain through pulses train. The pulses train carriers microwave frequency information, occurring the transient stimulated Brillouin scattering (SBS) effect with the counter-propagating optical chirp chain (OCC) wave in the optical fiber. The transient Brillouin spectra are periodically reconstructed in temporal domain. Through capturing the narrow linewidth transient Brillouin spectra reconstructed within each sampling period, the time-frequency relationship of microwave signals can be measured and restored, implementing the real-time high-accuracy microwave frequency measurement. The proposed scheme not only inherits the high-accuracy of the existing SBS-based schemes, but also achieves an improvement of temporal resolution by three orders of magnitude, and also has comprehensive performance such as multi-frequency microwave measurement and reconfigurable. As a high-performance solution, the microwave frequency measurement based on the OCC-transient SBS effect is only in its infancy, so more possibilities and applications can be expected in the future.
HIT is the only corresponding affiliation of the paper, Ph.D. candidate Wang Henan is the first author of the paper, and Prof. Dong Yongkang is the corresponding author. The research work was funded and supported by the National Natural Science Foundation of China, the National Major Scientific Research Instrument Development Project and the Heilongjiang Touyan Team Original Exploration Fund.
Link to paper: https://onlinelibrary.wiley.com/doi/10.1002/lpor.202200239
Experimental results of real-time frequency tracking of single-frequency time-varying microwave
