Dynamic compensation method for time-varying nonlinear error in the OFDR system based on reference vibration

A time axis dynamic calibration method based on a reference vibration signal is proposed to address the issue of temporal resolution deviation caused by laser scanning nonlinearity during hardware compensation of distributed optical frequency domain reflectometry (OFDR) technology. By introducing a high-stability reference vibration source at the front end of the fiber under test (FUT), a mathematical model is established relating the measured frequency, theoretical frequency, and system temporal resolution. Subsequently, a time calibration factor, derived from the reference vibration frequency ratio, is innovatively introduced to dynamically calibrate the temporal resolution of original vibration signals, thereby effectively suppressing frequency measurement errors caused by time axis distortion. The experimental validation demonstrates that within the frequency range of 10-120 Hz, this method can reduce frequency measurement error to 0.56%, which is one order of magnitude lower than the pre-calibration error, significantly improving the measurement accuracy of vibration frequencies. This method provides an effective frequency error compensation solution for OFDR technology, with broad application prospects in structural health monitoring, precision instrument diagnostics, and other fields.