Non-Ambiguous Microwave Frequency Measurement Based on Triple Electro-Optic Frequency Comb

Optical frequency comb serves as precise rulers in physical quantity measurements, using the Vernier measurement principle by configuring a multi-comb system. We propose a non-ambiguous microwave frequency measurement system based on triple comb generated by electro-optic modulation. The triple combs with slightly different repetition rates sample the unknown microwave signal. Utilizing mathematical principles of non-ambiguous measurement, the system achieves high-precision static signal measurements and real-time dynamic signal tracking. Limited by the modulation bandwidth of modulator, the system attains a detection range from 0 to 30 GHz. Leveraging the electro-optic comb’s flexibility, optical comb repetition rates can be tailored to receiver bandwidths. The dynamic range of microwave signal power is from -30 dBm to -10 dBm. In instantaneous frequency measurement of dynamic signal, errorfree measurement can be achieved at a resolution of 1 MHz. The spectral stability of the triple combs based on electro-optic modulation is not affected by temperature and vibration, which ensures that the microwave frequency measurement has a high robustness in a variety of measurement environments.