Limits to modulation rates of electroabsorption modulators

We analyze the speed limitations of optical electroabsorption modulators. We argue that modulation rate limits are closely related to quantum mechanical adiabaticity. By analyzing the breakdown of the adiabatic approximation, analytical expressions for modulation limits are found. These expressions are numerically validated. Furthermore, we discuss the constraints on the allowable modulation rate set by losses from the quantum well and transition linewidth.