Microwave photonic frequency measurement and time-frequency analysis: Unlocking bandwidths over hundreds of GHz with a 10-nanosecond temporal resolution

TL;DR

This paper presents a microwave photonic method for high-bandwidth frequency measurement and time-frequency analysis, achieving hundreds of GHz bandwidth and nanosecond temporal resolution with reduced hardware complexity.

Contribution

The authors introduce a dispersion-based frequency-to-time mapping technique with a V-shape FM signal and duty-cycle control, significantly improving bandwidth and resolution over previous solutions.

Findings

Achieved an analysis bandwidth of 252.8 GHz with 13.75 ns temporal resolution.

Reduced hardware requirements compared to existing microwave photonic solutions.

Demonstrated flexible temporal resolution by adjusting duty cycle.

Abstract

Fast and broadband spectrum sensing is an essential component in cognitive radio systems, intelligent transportation systems, electronic warfare systems, etc. However, traditional electronic-based solutions have a trade-off among the analysis bandwidth, temporal resolution, and real-time performance. In comparison, microwave photonic solutions can overcome the trade-off at the cost of frequency accuracy and resolution. Nevertheless, the reported microwave photonic solutions suffer from a very poor frequency resolution and impose extremely high requirements on hardware when the analysis bandwidth is close to or greater than 100 GHz. Here, we show a microwave photonic frequency measurement and time-frequency analysis method, which is implemented by dispersion-based frequency-to-time mapping and assisted by a specially designed V-shape linearly frequency-modulated signal and a duty-cycle-enabling technique. Compared with the reported microwave photonic solutions, the hardware requirements are greatly reduced when achieving similar performance conditions. Using a total dispersion of -6817 ps/nm and a V-shape linearly frequency-modulated signal with a bandwidth of 31.6 GHz and a duty cycle of 1/4, we achieve an ambiguity-free analysis bandwidth of 252.8 GHz, a corresponding temporal resolution of 13.75 ns and a frequency resolution of 1.1 GHz. The temporal resolution can be improved to 6.875 ns when the duty cycle is changed to 1/2, while the analysis bandwidth in this case is 126.4 GHz.