Abstract: By means of high-temperature physical drawing, glasses can be directly drawn into subwavelength-or nanometer-diameter fibers. As-fabricated nanofibers show excellent diameter uniformity and surface smoothness for low-loss optical wave guiding, and may exhibit a series of interesting properties such as tight optical confinement, evanescent guidance and high waveguide dispersion. These fibers provide promising building blocks for photonic applications in optical communications, optical sensing and nonlinear optics.