| 摘要 |
PURPOSE:To measure the difference in the propagation constant of an optical fiber non- destructively and easily with high accuracy, by applying a magnetic field of variable intensities for coupling of electromagnetic fields in the longitudinal direction of the optical fiber to be measured. CONSTITUTION:The linearly polarized light having the plane of polarization in parallel with the main axis at the incident end of an optical fiber 6 to be measured of a length L is made incident as incident light to the fiber 6 through a polarizer 3, etc. On the other hand, the exit light of the plane of polarization orthogonal with the polarizing direction of the incident light with respect to the main axis at the exit end of the fiber 6 is detected with a photodetector 9 by way of an analyzer 8, etc. If the intensity of the magnetic field in the longitudinal direction of the fiber 6 is changed by a solenoid coil 11, a variable resistor 13, etc., the coupling of elecdromagnetic fields changes. The Px(L)max at which the ratio of the exit light powder with respect to the incident light power attains a max. value is determined. The difference in the propagation constant DELTAbeta of the optical fiber, as calculated by the equationI, is measured non-destructively and easily with high accuracy by the easy operation which does not require cutting of the optical fiber. |
