Modeling and Analysis of the Electro-Optic Modulator With Alignment Errors

Electro-optic modulators have enabled a wide range of emerging applications that place greater demands on the alignment of the modulators. In this paper, for the first time to the best of our knowledge, we construct a theoretical model to describe the electro-optic modulator with alignment errors, which helps us to quantitatively analyze the distribution characteristics of the exiting intensity of the electro-optic modulator under different alignment errors and different applied voltages. The alignment errors in the theoretical model are divided into three kinds, namely, the horizontal error, the vertical error, and the rotation error. The theoretical results show that the model and the distribution characteristics of the exiting intensity are useful to align the electro-optic modulator precisely in practical applications. Furthermore, an experimental setup is proposed to align the electro-optic modulator based on a lithium niobite crystal and to verify the correctness of the model presented in this paper. An excellent agreement is found between the theoretical results and the experimental results.