Microwave Frequency Measurement Based on Optical Power Monitoring Using a Complementary Optical Filter Pair

An approach to the measurement of a microwave frequency based on optical power monitoring using a complementary optical filter pair is proposed and investigated. In the proposed system, a microwave signal is applied to a Mach-Zehnder modulator, which is biased at the minimum transmission point to suppress the optical carrier. The carrier-suppressed optical signal is then sent to the complementary optical filter pair, with the powers from the complementary filters measured by two optical power meters. A mathematical expression that relates the microwave frequency and the optical powers is developed. Experiments are performed to verify the effectiveness of the proposed approach. The performance of the proposed system in terms of the frequency measurement range, operation stability, and robustness to noise is also investigated.