Low-loss photonic crystal fibers

The lowest loss has been achieved in two types of photonic crystal fibre (PCF) due to an improvement of fabrication process. Optical loss at 1.55 /spl mu/m wavelength was 1 dB/km and the Rayleigh scattering coefficient was 2 dB/km /spl mu/m/sup 4/ in the type 2 PCF. These results suggest a possibility of low-loss PCF comparable to that of conventional single-mode fibers.