On-line measurement of a fiber loop mirror sensor using a set of adjacent wave-valley and wave-peak wavelengths.

In order to realize the on-line measurement of a birefringence fiber (BF) loop mirror (Bi-FLM) strain sensor with a short BF, the theoretical on-line measurements expression of a Bi-FLM strain sensor using a set of adjacent wave-valley and wave-peak wavelengths was deduced. The adjacent wave-valley and wave-peak wavelengths were near 1550nm and the BF initial conditions were used to calculate strain. The maximum error and minimum error of strain calculated by three different wavelengths combination were 0.0296% and -0.0003%, respectively. The result shows that the calculated strains are basically consistent with the given strains. The method doesn' t need human judgment. So it is helpful to realize on-line measurement by computer. The method is unrelated to the monitoring point. So the Bi-FLM sensor isn't calibrated. In addition, the method requires less information and only needs 0.5 period of interference waveform. So it is helpful to realize the on-line measurement of a Bi-FLM sensor with a short BF. [ABSTRACT FROM AUTHOR]