METHOD FOR MEASURING TRANSMISSION LOSS OF OPTICAL FIBER AND APPARATUS FOR EXECUTING IT

摘要

PROBLEM TO BE SOLVED: To measure a transmission loss of an optical fiber having a core and a sheath structure in detail and to particularly evaluate an influence on the loss of respective layers of the core of the fiber having a multilayer core. SOLUTION: An optical fiber 4 is disposed so that parallel optical beams irradiated from a light source 1 disposed on a linear rail 3 are incident on a center of an optical beam incident end face of the fiber 4, and emitting beam amount from the beam emitting end face of the fiber 4 is sensed by an optical beam amount sensing means 5. An incident angle of the beam to the incident end face of the fiber 4 is changed at an incremental width of about 0.1 by using an XYZΘstage 2. A transmission loss value is calculated based on a detected value of an emitting beam amount of each incident angle obtained for the optical fibers having two different lengths from a detected amount of an emitting amount by the means 5 by using a cutting-back method.