Agile photonic generation of arbitrary RF chirped waveforms based on a single CW laser

Abstract

Photonic generation of radio-frequency (RF) chirped signals has proven an attractive solution to overcome the limitations of conventional electronic waveform generators. However most of the designs proposed so far make use of a mode-locked laser as a broadband light source, resulting in high cost and complexity [1, 2]. Here we propose a much simpler concept of photonic generation of arbitrary RF chirped waveforms based on a frequency shifting loop (FSL) seeded with a single CW laser [3]. This simple scheme enables generation of on-demand RF chirps with large bandwidth (> 100 GHz), and fully controllable chirp sign, rate and envelope. The RF chirp duration can be adjusted from a few ns to hundreds of ns, resulting in time-bandwidth products (TBWP) exceeding 1000.