摘要:
PROBLEM TO BE SOLVED: To provide an optical fiber characteristic measuring apparatus and an optical fiber characteristic measuring method which are capable of improving spatial resolution more than conventional arts.SOLUTION: An intensity of x-polarized light can be reduced or increased at a specific frequency by subjecting the x-polarized light to intensity modulation by intensity modulation means synchronously with frequency modulation applied to the x-polarized light, so that an effective length of a Brillouin dynamic grating formed by the x-polarized light can be adjusted. As a result, a shape of a reflection spectrum of y-polarized light obtained by reflection on the Brillouin dynamic grating can be optimally adjusted, and thus spatial resolution in the y-polarized light can be improved.
摘要:
PURPOSE:To perform the measurement of a loss characteristic with good accuracy by reducing fluctuation, by allowing a linearily polarized optical pulse to be incident to an optical fiber to be tested through a polarized wave maintaining optical fiber and detecting back scattering light through the polarization maintaining optical fiber. CONSTITUTION:The optical pulse emitted from a pulse light source 1 passes through a polarizer 2 for permitting only the passage of a polarized light component in a definite direction, an optical directional coupler 3 and an optical coupling means 4 to be incident to a polarized wave maintaining optical fiber 10 from a coupling point A being an incident terminal. A polarization direction is set to an angle of 10-32 deg. to one of two orthogonal main axes of the optical fiber 10. Further, the pulse is incident to an optical fiber 5 to be tested through an optical coupling means 11 and a coupling point B and back scattering light reaches the polarizer 6 of the passing axis crossing the polarizer 2 at right angles from the optical directional coupler 3 through the reverse route to be incident to a light detector 7. The output of the detector 7 is subjected to averaging processing by an operational processing apparatus 8 to be displayed on a display apparatus 9.
摘要:
PURPOSE:To enable stable measurement, by inserting a depolarizer between a polarizing separation prism and a single mode optical fiber to be measured and exciting the non-polarization of the single mode optical fiber to eliminate the polarization dependence of back scattering light. CONSTITUTION:An optical fiber depolarizer 9 comprising a constant polarization optical fiber is inserted between the polarizing separation prism 4 of a pulse tester and a single mode optical fiber 6 to be measured. The depolarizer 9 is constituted by connecting two long and short constant polarization optical fibers 22, 23 so as to incline both of them at a predetermined angle and respectively connecting the same to single mode optical fibers 21, 24 and the length La, Lb of both constant polarization optical fibers 22, 23 are set to predetermined values. By this method, the polarization dependence of back scattering light of the single mode optical fiber 6 to be measured is eliminated and the irregularity in a measured value can be eliminated.