A Photonic Approach to Linearly Chirped Microwave Waveform Generation With an Extended Temporal Duration

A photonic approach to linearly chirped microwave waveform generation with an extended temporal duration is proposed and experimentally demonstrated. The linearly chirped microwave waveform generation is realized based on spectral-shaping and wavelength-to-time mapping, in which a Fabry-Perot (FP) interferometer with a linearly increasing or decreasing free spectral range is used to as a spectral shaper, and the wavelength-to-time mapping is realized using a recirculating dispersive loop with a large equivalent dispersion coefficient realized by allowing the spectrally shaped optical pulse to travel in the dispersive loop multiple times. The generation of two linearly chirped microwave waveforms at two different frequency bands with two temporal durations of 25 and 42 ns and a time-bandwidth product (TBWP) of 210 is experimentally demonstrated.