Ultrafast RF Spectrum Analyzer Assisted by Optical Short‐Time Fourier Transform

Ultrafast measurement of broadband radio frequency (RF) spectrum is of great importance in wireless communication, radar, remote sensing, and radio astronomy research. Among them, the RF spectrum analyzer based on the Optical Short‐Time Fourier Transform has received extensive attention and research. It can quickly perform the short‐time Fourier transform (STFT) at over 10 MHz frame rate in the optical domain and intuitively analyze the signal under test (SUT) with a bandwidth over 40 GHz. In this article, we review recent methods for performance improvement of an ultrafast RF spectrum analyzer based on STFT. The measurement frame rate has increased to 10 MHz to improve performance and support applications. All these recent efforts could inspire more innovative applications of temporal imaging modalities in the future.