Abstract
We present a method for determining crystallographic symmetry axes in an air-hole structure of a photonic crystal fiber (PCF) with a hexagonal structure. This method is based on the measurement of intensity distribution of the light transversely scattered from the PCF. The symmetry axes can be determined from the distinctive intensity pattern that is repeated for an axial rotation of the PCF. Simulations and experimental studies reveal that the technique is reliable and quite sensitive to the angle between the crystallographic symmetry axis and the launched light.