Effect of Temperature and Irradiation Intensity on the Harmonic and Intermodulation Performance of Mach-Zehnder Optomodulator
Muhammad Taher Abuelma’atti and Ali M.T. Abuelmaatti
This paper presents closed-form expressions for the amplitudes of the harmonics and intermodulation products resulting from driving a Mach-Zehnder optomodulator by a multisinusoidal RF voltage. These expressions are functions of the phase shift caused by the DC bias, φBIAS, and the modulator’s switching voltage, Vπ, required to change the output light intensity from its maximum value to its minimum value. The special case of a driving two-tone equal-amplitude RF voltage is considered in detail. The results show that the harmonic and intermodulation performance of the Mach-Zehnder optomodulator are strongly dependent on the parameters φBIAS and Vπ. These parameters are strongly dependent on many physical and chemical phenomena; for example irradiation intensity and temperature variations. Using the results obtained in this paper, a database can be established for the variation of the harmonic and intermodulation performance of Mach-Zehnder optomodulators with many physical and chemical phenomena. This would be of interest for any potential space application using Mach-Zehnder optomodulators where temperature and/or irradiation effects are of special concern. Simulation results obtained using the harmonic balance simulator controller in the Advanced Design System (ADS) design automation software are included.
Keywords: Mach-Zehnder optomodulator, Harmonics, Intermodulation