Patent ID: 7499173
Filing Date: 2009-03-03
Classification: G01B,H04B

Abstract:
1. A method for measuring a signal quality of light present in an optical communication medium, the light including at least one substantially coherent optical signal degraded by substantially incoherent optical noise, the method comprising the steps of: tapping a portion of the light from the optical communication medium; passing the portion of the light through a two-beam interferometer capable of introducing a specified delay into at least one light beam of a plurality of beams split from the portion of the light; measuring a light output power from said interferometer corresponding to a first specified delay setting; measuring a light output power from said interferometer corresponding to a second specified delay setting; determining relative magnitudes of the coherent optical signal and the incoherent optical noise based on the first and second light power measurements; computing a numerical value representing signal quality from the relative magnitudes of the coherent optical signal and the incoherent optical noise; and determining a numerical value of an optical signal-to-noise ratio.