Tunable microwave sawtooth waveform generation based on one single-drive Mach-Zehnder modulator

A photonic method of sawtooth waveform generation by using one single-drive Mach-Zehnder modulator is proposed and experimentally demonstrated. Depending on the polarization-sensitive characteristic of the modulator, the modulation sidebands and optical carrier can independently exist on two orthogonal polarization directions. Therefore, the required Fourier components can be manipulated on two polarization dimensions separately, and the superposition of the orthogonal optical envelopes synthesize a sawtooth waveform in time domain. The feasibility of the scheme is theoretically analyzed. In the experiment, sawtooth waveforms with full duty cycle at 3, 5, and 8 GHz are obtained, which agree with the simulation results well.