A frequency sextupling scheme for high-quality optical millimeter-wave signal generation without optical filter

Based on a laser with an integrated Mach-Zehnder modulator (IMZM), a novel frequency sextupling scheme is proposed for the millimeter-wave (mm-wave) signal generation in radio over fiber system. Theoretical analysis is presented to implement the two-tone optical frequency multiplication. The simulation results show that the high-quality frequency sextupling mm-wave signal can be generated without any optical or electrical filter. The optical sideband suppression ratio (OSSR) higher than 29 dB can be obtained without optical filter when the IMZM is consisted of three sub-MZMs with extinction of 30 dB. Furthermore, the influence of imperfect extinction ratio of the IMZM and nonideal phase difference between RF drive signal of two sub-MZMs of the IMZM on OSSR is investigated, and the quality of the generated optical mm-wave signal for two cases of the proposed scheme is also compared.

► The theoretical analysis and simulation verification of the proposed frequency sextupling scheme for high-quality optical mm-wave signal generation without optical filter are both presented.
► The relation between the extinction of the integrated Mach-Zehnder modulator (IMZM) consisted three sub-MZMs and single MZM is derived.
► Optical sideband suppression ratio (OSSR) for the IMZM with higher extinction ratio is more susceptible to nonideal phase difference of RF drive signal between two sub-MZMs.
► The imperfect extinction ratio of IMZM on OSSR is also investigated.