Photonic instantaneous RF frequency measurement system based on complementary modulation

A photonic instantaneous frequency measurement system based on complementary electro-optic modulation is proposed and experimentally demonstrated. A dual-electrode, dual-output Mach-Zehnder modulator is used to simultaneously achieve electro-optical 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 also robust to electrical circuitry imperfections.