Tunable dual frequency optoelectronic oscillator with low intermodulation based on dual-parallel Mach-Zehnder modulator

A tunable dual-frequency optoelectronic oscillator (OEO) based on dual-parallel Mach-Zehnder modulator (DPMZM) with low intermodulation is proposed and experimentally demonstrated. Two tunable electronic band-pass filters are used to select the oscillation modes of the two oscillating frequencies to achieve tunable dual-frequency OEO (TDF-OEO). Each of the two selected modes are modulated onto one sub-modulator of the DPMZM. By choosing proper bias conditions of the DPMZM, the intermodulation components generated by the dual-frequencies are suppressed. The tuning range of the TDF-OEO is from 1 GHz to 15 GHz in the experiment. We also discussed and experimentally demonstrated the tuning limitation of this dual frequency system.