Patent ID: 9042724
Filing Date: 2015-05-26
Classification: H04B,H04J

Abstract:
1. A device for measuring OSNR of a WDM optical signal including a plurality of wavelength channels, the device comprising: an input port; an optical train coupled to the input port and including serially connected a control unit coupled to the tunable optical filter, the polarization controller, and the photodetector, and configured to tune the optical filter to the selected wavelength channel; adjust the polarization controller to reach a target control point, at which the first optical power level is minimized or reduced; and compute the OSNR of the selected wavelength channel from a polarization extinction defined as a ratio of a second optical power level upstream the polarization selector to the first optical power level; wherein the control unit includes a computer processor and a non-transitory memory configured for causing the computer processor to perform a heuristic iterative search of the target control point by performing a plurality of iterations including a first iteration and a second iteration after the first, wherein a plurality of control points of the second iteration are selected based on optical power levels detected by the photodetector at a plurality of control points of the first iteration.