Patent ID: 7379235

Claim:
A method for reducing polarization dependence of a dispersion variation monitor, comprising: receiving an optical signal at a monitor, the optical signal comprising a plurality of components; splitting at a splitter the optical signal into a first polarized signal and a second polarized signal, the first polarized signal comprising a plurality of first photons, the second polarized signal comprising a plurality of second photons; receiving the plurality of first photons at a first material of a first detector, the first material having a band gap energy greater than or equal to a photon energy and less than or equal to two times the photon energy and operable to produce a reaction in response to two-photon absorption; receiving the plurality of second photons at a second material of a second detector, the second material also having a band gap energy greater than or equal to a photon energy and less than or equal to two times the photon energy and operable to produce a reaction in response to two-photon absorption; monitoring a first current resulting from two-photon absorption at the first material in response to receiving the plurality of first photons; monitoring a second current resulting from two-photon absorption at the second material in response to receiving the plurality of second photons; and establishing whether there is wavelength dispersion variation among the plurality of components in accordance with the first current and the second current by: determining if there is a change in a normalized current generated from the first current and the second current; and establishing that there is wavelength dispersion variation if there is a change in the normalized current.