Ultralow loss and long length photonic crystal fiber

We have succeeded in fabricating a low-loss and long length photonic crystal fiber (PCF) by improvement of fabrication process. The fiber is 10 km long and has a lowest loss of 0.37 dB/km at 1550 nm ever reported. We also succeeded in reducing the OH absorption loss to 3 dB/km. This is almost the half of the value ever reported. Using the low-loss PCF, we performed the first DWDM transmission experiment. DWDM signal of 8*10 Gbit/s is successfully transmitted through the PCF.