Controlling Actively Q-Switched Laser Output by Nonlinear State Feedback

Abstract

A powerful nonlinear controlmethodology known as feedback linearization is appliedin order to enhance the performance of Q-switched lasers. Specifically, anactively Q-switched laser system is described, where the desired output pulse shape is generated by nonlinear state feedback control. Open-loop performance is compared with closed-loop performance. After feedback is applied the system can still produce the desired output response even if the pump power is reduced or increased by a factor of two. Excellent approximation of the desired output profile can also be obtained with a 30% fluctuation in the stimulated emission cross section.