All-optical generation of full-range symmetry-tunable triangular-shaped pulses via wavelength multiplexing

Abstract

A novel, to the best of our knowledge, all-optical approach for generating full-range symmetry-tunable triangular-shaped pulses through wavelength multiplexing is proposed and experimentally demonstrated. Two light-waves with a specified wavelength interval are injected in parallel into two commercial push–pull Mach–Zehnder modulators (MZMs) to carry the baseband radio frequency input. A tunable optical delay line (ODL) followed by one MZM is utilized to introduce the desired phase shift. By multiplexing the modulated signals carried on two wavelengths, triangular-shaped pulses can be achieved by the opto-electronic conversion. In this approach, by simply adjusting the DC bias voltages and the delay time offered by ODL, the triangular-shaped pulse with any self-defined symmetrical coefficient can be obtained. A complete theoretical analysis on the operation principle is presented and verified. The triangular-shaped pulses with full-range tunable symmetrical coefficients at the repetition rate of 5 GHz are successfully generated. This approach features all-optical architecture, ultra-wide system bandwidth, full-range tunable symmetry (0%–100%) and excellent reconfigurability, which are highly desired for the high-performance triangular-shaped pulse generator.