A fiber-optic-taper loop probe includes first and second fiber segments, first and second tapering segments, and a center taper segment. In a preferred embodiment, first and second fiber segments are about 125 m in diameter, and the center taper segment has a substantially constant diameter of about 2-5 m. The fiber-optic taper forms a loop, the center taper segment remaining substantially straight and opposite the crossing point of the loop. The loop is secured to a support structure to maintain its shape and facilitate positioning relative to an optical component to be tested. The fiber segments may be connected to an optical characterization system including one or more light sources, lasers, detectors, spectrometers, etc. The geometry of the loop enables transverse-optical-coupling of the loop probe with an optical component without undesirable contact between other portions of the loop probe and other portions of the optical component and/or substrate.