Interferometer-free method for accurate characterization of an optical phase modulator

Abstract

Optical phase modulators find critical applications in classical and quantum communication for data modulation and in high-power fiber lasers for linewidth broadening. In this paper, we propose a simple interferometer-free method to accurately characterize an optical phase modulator. A radio frequency source is used to drive the phase modulator, and its output is observed on an optical spectrum analyzer (OSA). The relative power levels of the first and second-order side bands with respect to the optical carrier measured from the OSA are plotted as a function of the input RF power. These results are compared with the values expected through simulations where a parametric variation is carried out to find the value of $V_{\pi }$. We also present the details of characterization of other critical parameters of the phase modulator, such as electro-optic bandwidth, polarization-dependent loss, and its residual amplitude modulation.