Method and apparatus for identifying measurements of optical link performance that are unreliable

An apparatus, comprising:

• an optical network monitor connected to receive measurements of optical link performance from an optical network, the measurements being made at a coherent optical receiver of the optical network;
• wherein the optical network monitor is also configured to receive estimates of accumulated chromatic dispersion of an optical signal or a rate of change of said accumulated chromatic dispersion, the estimates being indicative of measurements at corresponding times by the coherent optical receiver that received the optical signal from an optical link of the optical network;
• wherein the optical network monitor is configured to identify at least one of the measurements of optical link performance as being unreliable in response to determining that the estimates indicate the accumulated chromatic dispersion of the optical signal varied at an above threshold rate near the time of the at least one of the measurements of optical link performance;
• and
• wherein the optical network monitor is configured to evaluate a weighted bit error rate from a subset of the measurements of the optical link performance in response to determining that the measurements of the subset were made near times that the estimates indicate that the accumulated chromatic dispersion of the optical signal varied slower than the threshold rate.

A non-transitory computer-readable medium comprising program instructions stored thereon for causing an apparatus to perform the steps:

• from an optical network, receiving estimates of accumulated chromatic dispersion of an optical signal or a rate of change of said accumulated chromatic dispersion, the estimates being indicative of measurements at a coherent optical receiver on the optical signal received from an optical link of the optical network at corresponding times;
• from the optical network, receiving measurements of optical link performance made at the coherent optical receiver in response to recovering data carried by the received optical signal;
• and
• identifying at least one of the measurements of optical link performance as being unreliable in response to determining that the estimates indicate the accumulated chromatic dispersion of the optical signal varied at an above threshold rate near a time corresponding to said at least one of the measurements of optical link performance;
• and
• evaluating a weighted bit error rate from a subset of the measurements of the optical link performance in response to determining that the measurements of the subset were made near times that the estimates indicate that the accumulated chromatic dispersion of the optical signal varied slower than the threshold rate.