Si optical modulator, one of the key components in Si photonic integrated circuits (PIC), should have good linearity performance so that the microwave photonic systems based on Si PIC can satisfy requirements in many applications. The linearity performance of Si optical modulators, including Si Mach-Zehnder modulators (MZM), is typically evaluated by third-order intermodulation distortion (IMD3) and spurious-free dynamic range (SFDR). In this presentation, we propose a new methodology to determine the IMD3 and SFDR values of Si MZMs accurately. Our model includes several characteristics of Si MZMs and, therefore, the model parameters should be extracted by various methods. Using the parameters, we simulate the values of the IMD3 and SFDR for a sample Si MZM. Examples of design optimization will be also presented based on this model to maximize the linearity performance of Si MZMs.
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