Computational-Experimental Design Framework for Laser Path Length Controller.

The application areas of piezoelectric materials are expanding rapidly in the form of piezo harvesters, sensors and actuators. A path length controller is a high-precision piezoelectric actuator used in laser oscillators, especially in ring laser gyroscopes. A path length controller alters the position of a mirror nanometrically by means of a control voltage to stabilize the route that a laser beam travels in an integral multiple of laser wavelength. The design and verification of a path length controller performance requires long (up to 3 months), expensive and precise production steps to be successfully terminated. In this study, a combined computational-experimental design framework was developed to control, optimize and verify the performance of the path length controller, without the need for ring laser gyroscope assembly. A novel framework was structured such that the piezoelectric performance characteristics were calculated using finite element analysis. Then, a stand-alone measurement system was developed to verify the finite element analysis results before system integration. The final performance of the novel framework was verified by a direct measurement method called mode-scanning, which is founded on laser interferometry. The study is concluded with the explanation of measurement errors and finite element correlations.