POLARIZATION MODE DISPERSION DISTRIBUTION MEASURING METHOD AND APPARATUS FOR OPTICAL FIBER

摘要

PROBLEM TO BE SOLVED: To provide a polarization mode dispersion distribution measuring method and apparatus which achieves measurement and computation of parameter values indicating polarization characteristics of a plurality of wavelength plates utilizing an optical time domain reflectomer practical used as a measuring apparatus of the propagation loss and back scattered characteristic distribution of optical fibers by accomplishing a modeling of an optical fiber to be measured in a serial connection of the plurality of wavelength plates. SOLUTION: An optical pulse having a desired angular frequency and a pulse width emitted from an optical pulse generator 1 gets the polarization thereof with a polarization controller 2 to be incident from one end 4a of an optical fiber 4 to be measured through a photocoupler 33. Receiving back scattered light from the optical fiber 4 through the photocoupler 3, a polarization state measuring part 5 outputs a stokes parameter. A Johns set computing part 6 inputs the stokes parameter at a desired time interval to be stored as time series data of the stokes parameter and the time series of a Johns set is computed for three kinds of polarization states from the time series data of the stokes parameter. A polarization mode dispersion distribution computing part 7 computes a parameter indicating the polarization characteristic of the optical fiber 4 using the time series of the Johns set. Thus, a polarization mode dispersion distribution of the optical fiber 4 is computed from the parameter indicating the polarization characteristic for two kinds of desired angular frequencies.