Optical Line System Physical Digital Model Calibration Using a Differential Algorithm

A computer-implemented method for calibrating a physical digital model of an optical line system (OLS) comprising a plurality of Erbium-Doped Fiber Amplifiers (EDFAs) and optical fiber spans, the method comprising:

• acquiring a first dataset of optical measurements of the OLS while the EDFAs are configured in a transparency mode by:
• (i) measuring an input power and an output power for each EDFA across a plurality of channels;
• and (ii) calculating a fiber attenuation profile for each optical fiber span from the measured input power and output power values;
• acquiring a second dataset of optical measurements of the OLS by:
• (i) systematically varying a target gain setting and a target tilt setting for at least one EDFA in the plurality of EDFAs across a defined granularity;
• and (ii) recording line telemetry data for each variation, the line telemetry data comprising a total optical power measurement from a photodetector in each EDFA and an optical spectrum measurement at a line termination;
• iteratively extracting physical parameters of the EDFAs and the optical fiber spans by:
• (i) selecting an EDFA, starting with a last EDFA in the OLS and progressing to a first EDFA;
• (ii) determining a numerical derivative of a measured power profile derived from the OSA measurement with respect to the varying target gain setting or a varying target tilt setting for the selected EDFA;
• and (iii) fitting at least one physical parameter of an adjacent optical fiber span or the selected EDFA using the computed numerical derivative to match a variation in the measured power profile;
• and
• calibrating the physical digital model of the OLS using the extracted fiber attenuation profile from the first dataset and the iteratively extracted physical parameters from the second dataset.