Patent ID: 7773207

Claim:
A method for determining a polarization mode dispersion (PMD) induced system penalty ε in an optical network carrying an optical wavelength division multiplexed (WDM) signal, the method comprising the steps of: tapping the optical WDM signal; separating an optical channel signal from the tapped optical WDM signal; performing a frequency-resolved state of polarization (SOP) measurement on the channel signal; in a computer, computing the polarization mode dispersion (PMD) induced system penalty ε as a function of L, wherein L is a weighted SOP string length based on the SOP measurement and expressed as: L = ∫ I ⁡ ( ω ) ⁢  d ⁢ ⁢ S / d ⁢ ⁢ ω  ⁢ ⅆ ω T ⁢ ∫ I ⁡ ( ω ) ⁢ ⅆ ω wherein: I(ω) is a weighting function comprising an optical spectrum of the signal; ω is frequency; S(ω) is frequency resolved state of polarization; and T is a bit period; and outputting the PMD-induced system penalty ε to an application for estimating a channel quality.