A practical, compact, high performance two-mode fiber acousto-optic frequency shifter

Due to the character of the original source materials and the nature of batch digitization, quality control issues may be present in this document. Please report any quality issues you encounter to digital@library.tamu.edu, referencing the URI of the item.Includes bibliographical references.Two-mode fiber acousto-optic frequency shifters demonstrated to date suffer in that they are not reliable and economically feasible. Class horns are used that are in efficient and not easily reproduceable. Also, the configurations require either a second acousto-optic interacion region, which limits the bandwidth over which good performance can be achieved, or a mode selecting direction coupler. These components add extra length and cost to the device. In this thesis new approaches are taken in developing the frequency shifter that allow for improvements in the areas of reliablity and cost. Horns machined out of aluminum are designed to have a resonance at the frequency of operation so that bigger tip movements can be obtained, allowing for a reduced interaction region. A static mode converter is used, replacing the second interaction region and allowing for a larger electrical bandwidth. Using these approaches, we have demostrated a device that gives 100% conversion of light at a wavelength of 1.0 pm using an interaction length of 3 cm without having to remove the fiber jacket, and having an electrical bandwidth of 64 KHz. This greatly reduces the size of the device and improves on the long term reliability. Using our results, we show what would make a good fiber for an optical wavelength of 1.3 gm