Generating Chirped Microwave Pulses Using an Integrated Distributed Fabry–Pérot Cavity in Silicon-on-Insulator

Abstract

We demonstrate photonic generation of chirped microwave pulses (CMPs) using an integrated distributed Fabry-Pérot cavity (DFPC) in silicon-on-insulator as a spectral shaper. The DPFC is based on a pair of spatially offset chirped Bragg gratings and has a response with varying free spectral range. The spectral shaper is used to filter broadband pulses from a mode-locked fiber laser, and CMPs are obtained at the output of a photodetector following a wavelength-to-time mapping process in a dispersive medium. We generate CMPs with a central frequency of up to 20 GHz, a radio-frequency (RF) chirp of 0.012 GHz/ps, and a time-bandwidth product of 14.5.