Fiber parameter identification

An electronic device configured for fiber parameter identification in an optical communications system, the device comprising:

• a processor;
• and
• a memory storing computer-executable instructions which, when executed by the processor, cause the device
• to calculate a plurality of C-matrices from a corresponding plurality of signals received at a receiver from a transmitter over a link in the optical communications system, each C-matrix comprising a plurality of C-coefficients representative of nonlinear noise in the received signal from which the C-matrix is calculated, wherein, for each of the plurality of received signals, a different amount of chromatic dispersion (CD) pre-compensation is applied at the transmitter, thereby minimizing signal nonlinearity at a different location in the link;
• and
• to identify, based on the plurality of C-matrices, one or more fiber parameter estimates corresponding to at least one of the different locations in the link.

An optical communications network comprising:

• at least one link comprising one or more optically amplified spans;
• and
• at least one electronic device configured
• to calculate a plurality of C-matrices from a corresponding plurality of signals received over a particular link of the at least one link, wherein each C-matrix comprises a plurality of C-coefficients representative of nonlinear noise in the received signal from which the C-matrix is calculated, and wherein, for each of the plurality of received signals, a different amount of chromatic dispersion (CD) pre-compensation is applied at a transmitter of the particular link, thereby minimizing signal nonlinearity at a different location in the link;
• and
• to identify, based on the plurality of C-matrices, one or more fiber parameter estimates corresponding to at least one of the different locations in the particular link;
• and
• a controller device configured to use the identified fiber parameter estimates to control a state of the optical communications network to achieve an objective.