Advancing microwave signal generation: frequency quadrupling using dual-drive Mach-Zehnder modulator

Abstract

This work demonstrates the implementation of a microwave photonic technique for generating a frequency-quadrupled microwave signal. The approach involves utilizing a parallel Dual-Drive Mach-Zehnder Modulator (DDMZM) driven by an electrical signal, while applying appropriate dc biasing to the DDMZM electrodes to suppress or eliminate the odd harmonic components of the sidebands in the optical domain. The DDMZM is operated at its maximum transmission point (MATP). To eliminate the optical carrier, an optical notch filter with the same central wavelength as the carrier is employed at the output of the DDMZM. This setup yields two optical sidebands. By detecting the beat signal at a photodetector (PD), a fourfold increase in frequency relative to the input RF signal is achieved. The input microwave signal frequencies of 15 GHz are utilized, resulting in output microwave signal frequencies of 60 GHz, 120 GHz, respectively. The generated frequency-quadrupled microwave signal can find applications in areas such as high-speed communication systems, radar systems, wireless networks, and satellite communications, where higher frequency signals are desired.