Application of hydrofluoric acid's corrosive properties in the fabrication of photonic crystal fibers

We introduce a new fabrication method for photonic crystal fibers (PCFs) using the hydrofluoric acid's corrosive property. The transversal structure of a PCF can be changed by filling its air-holes with hydrofluoric acid, which corrodes the glass wall around and therefore widens the air-holes. By accurately controlling the hydrofluoric acid corrosion time, we can enlarge the air holes up to millimeter precision. This method can be used as a supplement of the traditional fusing-drawing technology to realize more complicated structures of PCFs in practice. Meanwhile, this method greatly modifies the light-guiding properties of PCFs. Experimental results indicate that, with the increase of corrosion time, the leakage loss and the scattering loss will decrease, the nonlinear coefficient will increase, the effective refractive index of fundamental mode and the equivalent refractive index of cladding will decrease, and the group velocity dispersion will be modified accordingly.