Patent ID: 7440170
Filing Date: 2008-10-21
Classification: H04B

Abstract:
1. An optical signal-to-noise ratio (OSNR) monitoring apparatus comprising: an optical tunable filter having a periodic transmittance passband for filtering an optical communication channel carrying a signal and a noise, the transmittance passband having a minimum transmittance and a maximum transmittance, wherein the optical tunable filter is an optical delay interferometer; a tuning control unit for tuning the transmittance passband of the optical tunable filter between the maximum and minimum transmittances; an optical power detector for measuring a power of the filtered optical communication channel; and a processing unit for determining the OSNR of the optical communication channel based on maximum and minimum powers measured by the optical power detector, wherein the power is measured at least 10 times as the tuning control unit tunes the transmittance passband of the optical tunable filter between the maximum and minimum transmittances.