This article proposes a process to manufacture optical fiber shape sensors for biomedical applications. By using polymer extrusion on three optical fibers, a triplet with a diameter below 600 μm is obtained which can be inserted into surgical needles or catheters. Furthermore, the fiber triplet position within the coating and the angle of the triplet are parameters that need to be controlled, to enable the best performance. The radial and angular positions of the optical fibers in the triplet are measured with an accuracy of 3μm and 4 degrees, respectively. The sensor incorporating our recently developed ROGUEs (random optical fiber gratings written by UV or ultrafast laser exposure) backscatter enhanced fibers, is then used for shape sensing demonstration with an OFDR technique.