Theme 1.4: Multimaterial Multifunctional Fibers

The overall goal of this theme is the development of multimaterial multifunctional fiber devices. Virtually all electronic and optoelectronic devices necessitate the prescribed assembly of conducting, semiconducting and insulating materials into specific geometries with intimate interfaces and microscopic feature dimensions. While a variety of wafer-based processes have been developed to deliver these requirements, all are inherently restricted by the wafer size, its planar geometry and the costs associated with the large number of consecutive high precision processing steps. In contrast, the technique of optical fiber drawing from a macroscopic preformed rod is simpler and yields extended lengths of highly uniform fibers. So far, this technique has been restricted primarily to insulating materials, simple geometries and large features. Recently, a new family of fibers composed of conductors, semiconductors and insulator has emerged. These fibers while sharing the basic device attributes are fabricated using conventional fiber processing approaches thus yielding kilometers of functional fiber devices. Under this theme we will be focusing on the development of a canonical set of unifunctional fiber devices including: wavelength-scalable hollow-core transmission fibers; Fabry Perot fiber resonators; transverse surface emitting fiber lasers; thermal and optical fiber detectors and piezoelectric fibers.  While each device presents unique materials selection and processing challenges there are significant overlapping issues that unite these two research objectives. One of the common challenges is that of electrical activation. To that end we will need to provide continuous electrical contacts running through the entire fiber forming intimate contact with the active medium. Since metallic elements are crystalline they will undergo a phase transition and thus will form a low viscosity liquid during the fiber draw process. This in turn will generate ample opportunity for capillary breakup. The conditions and structures that lead to the preservation of cross section from the perform to drawn fiber will be elucidated. Future improvements in fiber materials and additional geometric and feature control will enable the delivery of semiconductor device functionality at fiber optic length uniformity and cost and present significant opportunities for fabrics with system level sophistication to be developed under theme 5.2.

Theme 1.4 Researchers

Prof. Yoel Fink, Department of Materials Science and Engineering
Prof. John D. Joannopoulos, Department of Physics
Prof. Steven G. Johnson, Department of Mathematics

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