Theoretical Analysis and Measurement on the Character of Bending Loss in Fiber

In order to reduce the bending loss in long distance fiber communication and use the bending loss in fiber laser to obtain the single mode output,velocity method is introduced to explain the mechanism of bending loss in fiber.Marcuse theory is adopted to research the variation between the bending loss and bending radial,wavelength and the radial of fiber core.By the computer simulation,we can draw the conclusion that with the reducing of bending radial,the increasing of wavelength and the increasing of the radial of fiber core,the bending loss is increasing,the bending loss of higher mode is higher than that of low mode.We can reduce the bending loss in long distance fiber by controlling the bending radial lower than the critical radial.We can obtain the single mode output in fiber laser by increasing the radial of mode field.