THE PRESENT INVENTION RELATES TO AN APPARATUS (100) TO MOUNT A CAPILLARY (200) FOR USE IN FABRICATING A FLAT MICROSTRUCTURED FIBER. THE APPARATUS (100) COMPRISES A FIRST MEMBER (101) CONFIGURED FOR HOLDING A PREFORM (300); AND A SECOND MEMBER (104) COUPLED TO THE FIRST MEMBER (101) HAVING AN EXTENSION (106) EXTENDING FROM THE BODY FOR ENGAGING A PORTION OF THE CAPILLARY (200) POSITIONED IN THE PREFORM (300). THE APPARATUS ALSO COMPRISES A CONNECTING MEMBER (103) THAT COUPLES THE FIRST MEMBER (101) WITH THE SECOND MEMBER (104). THE APPARATUS (100) TO MOUNT THE CAPILLARY (200) IS CAPABLE TO PREVENT DEFORMATION AND MISALIGNMENT OF THE AIR HOLES IN THE FLAT MICROSTRUCTURED FIBER. FIGURE 1