A method for manufacturing a bundle of fibers for use as a capacitor is disclosed. First and second fibers all having an electrically conductive fiber core and an electrically insulating cladding are provided and arranged in a bundle. The first end of the first fibers are arranged to protrude from a first end of the bundle, and the second ends of the second fibers are arranged to protrude from a second end of the bundle creating a plurality of first and second spaces defined by the protruding first and second ends of the first and second fibers and the non-protruding first and second ends of the second and first fibers respectively. The first and second spaces are filled with an electrically insulating material. First and second electrodes are provided that contact the fiber cores of the first and second fibers respectively so that an electric capacitance is established between the fiber cores of the first fibers and the fiber cores of the second fibers.
 This invention was made with government support under Contract No. DE-AC05-00OR22725 awarded by the U.S. Department of Energy. The government has certain rights in the invention.