Photonic chirped radio-frequency generator with ultra-fast sweeping rate and ultra-wide sweeping range.

A high-performance photonic sweeping-frequency (chirped) radio-frequency (RF) generator has been demonstrated. By use of a novel wavelength sweeping distributed-feedback (DFB) laser, which is operated based on the linewidth enhancement effect, a fixed wavelength narrow-linewidth DFB laser, and a wideband (dc to 50 GHz) photodiode module for the hetero-dyne beating RF signal generation, a very clear chirped RF waveform can be captured by a fast real-time scope. A very-high frequency sweeping rate (10.3 GHz/μs) with an ultra-wide RF frequency sweeping range (~40 GHz) have been demonstrated. The high-repeatability (~97%) in sweeping frequency has been verified by analyzing tens of repetitive chirped waveforms.