Design of electro-optic frequency shifters

Abstract

Thesis (Ph.D.)--University of Rochester. College of Engineering and Applied Science. Institute of Optics. This thesis was digitized by the Institute of Optics in 2014 and was determined to have lapsed into the public domain. If you are the author and have questions about the digitization of your work, please contact Kari Brick, Graduate Program Coordinator for the Institute of Optics, at [email protected]. Other contact information for the Institute is available at http://www.optics.rochester.eduThis thesis describes a theoretical investigation of electrooptic frequency shifters for possible use in interferometric applications (Heterodyne Interferometry), and an experimental investigation of some of the principal theoretical predictions. After recalling the basic properties of electrooptic crystals, we start from the known design of a two-crystal, sinusoidally excited modulator, and examine the possibilities of improvements by the use of more than two crystals. Although the theoretical conversion efficiency and spectral purity are improved by the addition of more crystals, it is shown that, in practice, the two crystal modulator competes favorably with other designs. This particular set-up is then studied in detail, in the two configurations in which it may be used. By means of the Jones calculus, we determine the reduction in performance caused by errors in various system parameters. The field of view of the modulator is evaluated, as well as the decrease in performance when the crystals are not anti-reflection coated. The experimental study of two-crystal frequency shifters shows that the system operates very near its theoretical limits in both configurations. The mechanical and electrical tolerances are rather easy to meet, but the quality of the optical elements must be high to insure a high degree of spectral purity in the output