Optical generation of linearly chirped microwave pulses using fiber Bragg gratings

We demonstrate a new method to generate broad spectrum chirped microwave pulses using an electrooptical system. Two fiber Bragg gratings and a mode-locked fiber laser were used to generate pulses with a linear frequency chirp. The bandwidth of the microwave pulses can be significantly broader than the bandwidth that can be obtained using electronic systems. The parameters of the chirp can be easily controlled by adjusting the parameters of the optical system. The same method can be used to generate microwave pulses with a complex frequency modulation.