Recent Progress in Electro-Optic Modulators: Physical Phenomenon, Structures Properties, and Integration Strategy

Electro-optic modulators (EOMs), serving as indispensable components within photonic integrated circuits, are essential for enabling energy-efficient, high-speed, and high-capacity optical communication systems. This review illustrates the principal physical phenomenon exploited in EOMs and provides a comprehensive analysis of the cutting-edge EOMs featuring interference structures (Mach–Zehnder modulators and Michelson-interferometer modulators) and resonance structures (microring modulators, racetrack modulators, and photonic crystal modulators). The comparative analysis of the performance merits and limitations in EOMs is presented, highlighting the combination of diverse electro-optic material compositions with different optical structures, which reveals a promising integration strategic so as to pursue a trade-off in modulation performance. It is contributed to the ongoing discourse on optimizing EOMs for the subsequent communication technologies and the advancement of photonic chips.