Tensile strength and failure behavior of bare single mode fibers

•We investigate tensile strength and failure behaviors of bare SMFs.•At 24 °C, Weibull modulus varys inversely with the increasing gauge length.•The fracture initiates from the outer cladding surface.•As testing temperature increases to 900 °C, the tensile strength decreases. We have investigated systematically the tensile strength and failure behavior of bare single mode fibers (SMFs) prepared by mechanical stripping technique. The tensile strength of bare SMFs under different temperatures is analyzed based on Weibull statistics. At room temperature, the bare SMFs show lower tensile strength than the SMFs with coating. The Weibull modulus referring to the width of the tensile strength distribution decreases when the gauge length of bare SMFs increases. The fractographic examination indicates that the fracture initiates from the outer cladding surface. As testing temperature increases from room temperature to 900 °C, we find that the tensile strength of bare SMFs decreases for the reason of the structural surface relaxation of SMF. The Weibull modulus decreases firstly then increases. Such change of bare SMFs is due to the partial restoration of flaws on fiber surfaces as testing temperature increases. The obtained results could provide guidance for the application of bare SMF prepared by mechanical stripping technique in harsh environment.