Polarization-maintaining optical fiber as a sensor of shell vibrations

The objective of this work was to investigate the effect of perturbations resulting from both winding a polarization-maintaining (PM) optical fiber on a cylindrical shell in a helical configuration, and radial displacements of the shell on the polarization properties of the light transmitted in the fiber using Mueller matrix polarimetry. A comprehensive, phenomenological theoretical formalism using Mueller matrix calculus was developed to describe the polarization state of light transmitted in a helically wound optical fiber with uniform birefringence and perturbations along the length. This formalism can be used as the basis to model and understand more complex perturbations and polarization effects. A comparison degree of linear polarization obtained from the polarization model in this work and an existing model widely used in the literature, which did not include birefringences due to the fiber configuration, yielded significant differences. The birefringences associated with the fiber configuration must be included in order to develop an accurate polarization model. An optical fiber polarimeter was developed to determine experimentally the Mueller matrix of the fiber in order to study the effect of perturbations on the polarization properties of the transmitted light. Results of experimental measurements of the polarization properties of the PM fiber are discussed. Results of measurements of the polarization properties of the PM fiber wound on a piezoelectric cylindrical shell that is excited to produce both static and dynamic, uniform radial displacements are given. Finally, the effect of radial displacements from low frequency vibrations of a thin, cylindrical steel shell on the polarization properties are also discussed. This work serves as the foundation for understanding the effect of external perturbations on the polarization properties of optical fibers, and establishes the proof-of-principle for developing a polarimetric sensor using polarization-maintaining optical fiber and Mueller matrix polarimetry. Recommendations for future research are also given.