Photonic Instantaneous Frequency Measurement System Using Complementary Modulation

A novel photonic instantaneous frequency measurement system based on complementary modulation is proposed and experimentally demonstrated. A dual-electrode dual-output Mach-Zehnder modulator is used to simultaneously achieve electrooptical modulation and complementary modulation sideband (MS) filtering. By suppressing the optical carrier at one of the modulator outputs, complementary MS filtering is mapped into two complementary average optical powers from which the RF frequency is derived. The obtained frequency measurement is independent of both optical and RF powers, and is also robust to electrical circuitry imperfections.