Photonic Generation of Multi-Band Linearly Frequency-Modulated Signal Based on a Dual-Parallel MZM

A photonics-based approach for multi-band linearly frequency-modulated (LFM) signal generation is proposed and demonstrated by using a dual-parallel Mach-Zehnder modulator (DP-MZM) injected by a dual-band LFM signal with opposite chirp rates. The dual-band LFM signal is applied to the DP-MZM that is biased as a frequency quadrupler via a 90° hybrid coupler. The 1st-order and the 2nd-order optical sidebands of the dual-band LFM signal, as well as two single-tone optical sidebands, are generated at the output of the DP-MZM due to the nonlinearity of the modulator and the non-ideal bias condition. After the optical signal from the DP-MZM is detected in a photodetector, multi-band LFM signals with multiplied bandwidth are generated. The generation of the two single-tone optical sidebands from the dual-band LFM signal greatly increases the number of the generated LFM signals. An experiment is conducted to verify the approach. Eight LFM signals up to 27 GHz in different frequency bands are simultaneously generated. The performance of the multi-band LFM signal including frequency recovery and pulse compression capability is also verified.