We present a prototype for the first tracking detector consisting of 250 mu m thin scintillating fibers and silicon photomultiplier (SiPM) arrays. The detector has a modular design, each module consists of a mechanical support structure of 10 mm Rohacell foam between two 100 mu m thin carbon fiber skins. Five layers of scintillating fibers are glued to both top and bottom of the support structure. SiPM arrays with a channel pitch of 250 mu m are placed in front of the fibers.