Precise Identification of Wideband Multiple Microwave Frequency Based on Self-Heterodyne Low-Coherence Interferometry

Frequency estimation of microwave signals is a crucial functionality for applications ranging from biomedical engineering to electronic warfare systems. Photonics-based frequency measurement systems offer advantages of flexible reconfigurability and wide bandwidth compard to electronic methods. However, photonic based systems are limited by trade-offs between measurement range and accuracy. Here, we propose and experimentally demonstrate a frequency identification system with ultrahigh accuracy of 900 kHz, large bandwidth of 39 GHz, and the capability of multiple frequencies estimation. The great performance is achieved by wideband distributed frequency-to-power mapping created by self-heterodyne low-coherence interferometry. The results show that the system we proposed is beneficial for applications in RF spectrum sensing of modern communication and radar applications.