Abstract

A photonic approach for generating an amplitude- and phase-modulated microwave signal with tunable frequency and modulation bit-rate is proposed. Two coherent optical wavelengths are sent to a fiber Sagnac interferometer (SI) incorporating an optical phase modulator (PM), a fiber Bragg grating (FBG) notch filter and a Mach–Zehnder modulator (MZM). With one sideband being amplitude-modulated at MZM and the other being phase-modulated at PM, a frequency-tunable amplitude- and phase-modulated microwave signal is generated by beating the two sidebands at a photodetector (PD). The proposed technique is investigated theoretically. The generation of a 20 GHz amplitude-modulated microwave signal, a 20 GHz phase-modulated microwave signal, a 25 GHz amplitude- and phase-modulated microwave signal with tunable modulation bit-rate is demonstrated.

© 2013 Optical Society of America