We describe a modified fabrication process to reduce spectral attenuation in highly nonlinear photonic crystal fibers (PCF) by reducing the effect of OH(-) content in the silica glass. In particular we show outstanding results for small core sizes of 2 mu m diameter including an attenuation of 10dB/km at the OH(-) peak wavelength of 1384nm, by annealing the preform prior to the fiber draw.
Gris-Sanchez, I., Mangan, B. J., & Knight, J. C. (2011). Reducing spectral attenuation in small-core photonic crystal fibers. Optical Materials Express, 1(2), 179-184. https://doi.org/10.1364/OME.1.000179