Patent ID: 8655185

Claim:
An optical node disposed along a transmission line that uses optical fibers, the optical node comprising: a signal generator configured to generate a first measurement signal for measuring polarization mode dispersion values, and transmit the first measurement signal to a downstream optical fiber of the transmission line; and a monitor configured to detect a second measurement signal from an upstream optical fiber of the transmission line, and measure polarization mode dispersion values by performing signal processing with respect to the second measurement signal, wherein the first measurement signal generated by the signal generator uses a wavelength of a supervisory control signal for supervising and controlling a primary signal, wherein the monitor includes a divider configured to divide the polarization components of the second measurement signal into mutually orthogonal horizontal and vertical components, one or more optical detectors configured to take the optical signals for the horizontal and vertical components divided by the divider, and opto-electrically convert the optical signals into electrical signals, one or more analog-to-digital converters configured to digitally convert the analog detection values of the one or more optical detectors, a signal processor configured to apply digital signal processing to the digital detection values converted by the one or more analog-to-digital converters, and thereby compute coefficients used to compute the polarization mode dispersion values, a controller configured to compute the polarization mode dispersion values on the basis of the coefficients output by the signal processor, a clock recovery unit configured to recover the timing of the second measurement signal; and an equalizer configured to accept as input the respective phase components of the second measurement signal after passing through the clock recovery unit, and periodically output FIR filter coefficients, wherein a trigger for obtaining polarization mode dispersion values is periodically transmitted with respect to the signal processor, and wherein the controller includes a first storage configured to store the coefficients output from the signal processor on the basis of the transmission of the trigger, and a calculator configured to calculate the polarization mode dispersion values on the basis of the coefficients stored in the first storage.