Angular orientation of micro-structured fiber by side imaging analysis

A side-imaging technique (SIT) for orienting the azimuthal angle of micro-structured fiber (MSFs) is proposed and demonstrated. Scattering is reduced by using the incoherent light as illuminating source. Side images are measured and analyzed while the fiber is rotated. The peaks pattern of the side-images, unique to each MSF, are experimentally demonstrated to be correlated closely with the symmetry in the cladding structure of MSFs. The unique correspondence between the peaks and the azimuthal angle is determined by numerical simulations.