High-resolution microwave frequency measurement based on dynamic frequency-to-power mapping

Abstract

In this paper, we propose a microwave frequency measurement system that simultaneously achieves a large measurement range, high resolution, and linear frequency mapping in a compact configuration with a single laser and photodetector. The system is based on a novel dynamic microwave amplitude comparison function (ACF), which performs the power comparison in cascaded time intervals. The continuous movement of the dynamic ACF generates a series of steep and linear frequency-to-power mapping intervals, which can be seamlessly pieced together without sacrificing the frequency measurement range, thus breaking the trade-off between measurement resolution, linearity, and range. The proposed frequency measurement system is experimentally demonstrated by using an integrated silicon-on-insulator (SOI) microring resonator with an optical bandwidth of 1.8 GHz and outperforms current solutions by achieving a measurement resolution of over 80 dB/GHz throughout a frequency measurement range up to 20 GHz. Meanwhile, the highly linear system shows excellent accuracy where the average measurement error throughout the range is only 47.2 MHz, which is around 0.31% of the total measurement range.