Abstract: Theoretical formula of single-mode fiber bending loss coefficient change with bending radius is simulated. The bending loss coefficients of single-mode fiber winding in 1 circle under normal and high temperature and humidity conditions at 1550 nm are measured. The measured results are drawn into curves and compared with the theoretical curves obtained by simulation. The bending loss coefficients of fiber binding in 2, 3 or 4 circles under normal temperature, high temperature and humidity, salt mist and vulcanization are measured and compared with those in 1 circle. The difference is identified and the reason caused that are analyzed by comparison. Results show that the bending loss coefficients of the fibers with bending radium from 15 mm to 23 mm are approximately linear with the winding circle number in these four environments.

Key words: fiber, bending loss, high temperature and humidity, salt mist, vulcanization