Optical generation of millimeter-wave signals via frequency 16-tupling without an optical filter

Abstract

Microwave frequency multiplication using two cascaded dual-parallel Mach–Zehnder modulators (DP-MZMs) to generate an optical millimeter-wave (mm-wave) with 16-tupling of the radio frequency (RF) driving signal frequency is proposed. A theoretical analysis leading to the optimum operating conditions including the direct current (dc) bias points, the modulation index, and the phase difference between RF driving signals is developed and demonstrated. A 160GHz mm-wave with an optical sideband suppression ratio (OSSR) of 21.5dB and a radio frequency spurious suppression ratio (RFSSR) of 38dB is generated from a 10GHz RF driving signal, which largely reduce the frequency of electrical driving signal and electrooptic devices. Since no optical filter is employed to suppress the undesired optical sidebands, the system exhibits the advantage of large frequency tunable range.