The paper presents a new concept of micro-artefact, the fiber gauge, consisting of a set of optical fibers sticking out from a flat surface. The fibers are arranged as a regular array of different height cylinders, with aspect ratios up to 20:1. The artefact is produced taking advantage of optical fibers manufacturing technology, featuring relatively high geometrical accuracy, combined with very good mechanical properties. The fiber gauge can be applied to calibration of most contact or non-contact instruments for characterization of surface topographies and 3Dmicro-geometries, such as micro- or nano-CMMs, optical instruments, etc. Different designs and dimensions allow for realization of structures that can be adapted to various instruments calibration needs. Development, analysis and application of prototype artefacts are reported.