Self-Referenced and Wide-Range Tunable Microwave Frequency Measurement Using Period-One Oscillation and Spectral Gating.

We demonstrate a reconfigurable microwave frequency measurement (MFM) scheme based on the period-one (P1) dynamics of an optically injected semiconductor laser. Unlike conventional architectures relying on electrical frequency-sweeping, our approach utilizes the P1 oscillation to generate a wideband linear optical chirp. A spectral gating mechanism is introduced, where an optical bandpass filter creates a negative temporal marker by rejecting free-running component of distributed feedback laser (DFB), thereby eliminating the need for external synchronization or pilot tones. The measurement range is flexibly tunable by adjusting the injection parameters, enabling a measurement range from 10 to 48 GHz. Experimental results demonstrate a frequency resolution of 50 MHz with chirp rate of 1 GHz/μs and a root-mean-square (RMS) error below 15 MHz, confirming the validity of this all-optical, self-referenced frequency-to-time mapping technique.