This work concentrates on the study, analysis, and development of rare-earth-based optical fiber active devices. The properties of the neodymium ion are analyzed and related to its potential role in the operation of various active optical devices. Existing technology in rare-earth-based fiber amplifiers is reviewed. Novel techniques for the fabrication of rare-earth-based glass rods and fibers are presented. Further, a discussion of results and ideas for the point sensing of temperature, and the simultaneous sensing of temperature and strain using optical time-domain reflectometry techniques with such devices is also presented. / Master of Science