Design and Characterization of a Tunable Fabry-Perot Filter using an Electro-Optic Modulated Spacer Layer

Tunable Fabry-Perot filters are used in several commercial and research areas. Using an electro-optic material as a spacer layer provides an efficient way to modulate the optical path length of the etalon cavity. The design and characterization of a tunable Fabry-Perot using an electro-optic polymer as the spacer layer has been performed. The clamped Fabry-Perot devices with finesses of 40-60 showed a quadratic peak shift with applied voltage. Creep was observed in the clamped devices and a theoretical model using a viscoelastic liquid Generalized Kelvin-Voigt configuration was developed to account for the clamp's contribution to the peak shift. Glued Fabry-Perot devices were fabricated and found to have an air gap. Theoretical models taking into account the air gap were developed to explain the peak shift. The glued devices also showed a quadratic dependency with applied voltage. The measured values for the peak shift were compared to predicted values using the electro-optic coefficient r13, piezoelectric coefficient d33, and Young's modulus Y of the glue