Abstract : The principal objective of this research program is to develop single-crystal (SC) fibers for use in nonliner optical devices. This encompasses measurement of physical and chemical properties of several candidate materials, fabrication of SC fibers, and investigation of nonlinear optical applications. This report describes the successful fabrication of several SC fibers using new growth techniques and progress with hybrid fibers which show great promise for nonlinear optical applications. Keywords include: Fiber optics, optical materals, single cyrstal fibers, evanescent wave coupling, and hybrid fibers.