Photonics-assisted microwave frequency measurement based on high-Q micro-ring resonator

We demonstrate a high-performance microwave frequency measurement system based on a silicon photonic chip, employing a tunable high-Q micro-ring resonator (Q ≈ 7.5×10⁵) and multi-channelization technology. The system employs an eight-channel optical sideband scheme, partitioning a wideband microwave signal into discrete sub-bands for parallel processing. A Mach-Zehnder-interferometer-coupled micro-ring resonator, tunable via voltage over time, maps microwave spectral information to the time domain. By carefully aligning the resonator’s free spectral range (FSR) to slightly exceed the channel spacing, the system achieves simultaneous multi-channel demultiplexing and detection, enabling rapid and broadband frequency identification. Experimental validation confirms a measurement range of 0-40 GHz, with a single-frequency error of 68.95 MHz and an intra-channel multi-frequency resolution of 261.53 MHz. These results highlight the system’s promise for high-speed, high-resolution electrical spectrum analysis.