Photonic Generation of Frequency-Quadrupled Microwave Signal With Tunable Phase Shift

A photonic scheme for frequency-quadrupled microwave signal generation with full 360 ° arbitrarily tunable phase shift is proposed and experimentally demonstrated. Two coherent optical components are generated by biasing a Mach-Zehnder modulator at maximum transmission point to suppress odd-order sidebands. Then, two second order sidebands together with the optical carrier are sent to a programmable filter to reject the optical carrier and introduce a phase shift to one of the second order sidebands. A frequency-quadrupled microwave signal with tunable phase is finally obtained by beating the two sidebands at a photodetector. Tunable phase shift of full 360 ° with a microwave frequency from 30 to 42.4 GHz is experimentally demonstrated. The proposed approach has potential applications in the broadband array signal processing system.