Photonic generation of a parabolic-shaped microwave signal and dual-linear-chirp microwave waveform.

Based on an external modulation technique through a dual-polarized dual-parallel Mach-Zehnder modulator, a photonic technique is proposed for the generation of a microwave signal with a parabolic shape. An optically modulated waveform from the modulator is passed through an optical bandpass filter, which results in parabolic signals of 1 GHz and 9 GHz frequencies at the photo detector. A peak power spectral component of -30 power is obtained at 1 GHz and 9 GHz frequencies of the parabolic signal. Based on the present methodology, a parabolic signal of the desired frequency band can be obtained. The obtained signal is processed to generate a dual-linear-chirp signal by passing through the phase modulator. Here, a dual-linear-chirp microwave waveform with a chirp rate of 1.53×10/ is achieved at 6 GHz center frequency. The results are obtained through MATLAB simulation and verified by experimental results. A fair agreement is found between the result obtained through MATLAB simulation and the result obtained by experimental verification.