Theoretical Analysis of the Intermodulation Performance of Mach-Zehnder Modulators with Difference Frequency Injection

Abstract

Large signal analysis of Mach-Zehnder electro-optic modulators excited by three tone signals is presented. The special case of two equal-amplitude sinusoids plus a difference-frequency injection is considered in detail. The results show that even under large signal conditions it is possible, at least in theory, to totally eliminate the third-order intermodulation when the amplitudes of the equal-amplitudes input sinusoids and the difference-frequency injection are equal. This would be a promising technique for achieving highly linear Mach-Zehnder electro-optic modulators.