Simultaneous measurement of strain and temperature with a multi-longitudinal mode erbium-doped fiber laser

A multi-longitudinal mode erbium-doped fiber laser sensor system for simultaneous measurement of strain and temperature is proposed and experimentally demonstrated. The beat frequency signal of the laser shifts with both strain and temperature, while, the output power of the laser only changes with temperature because of the erbium-doped fiber used in the laser cavity. By monitoring both of the beat frequency signal and the output power, the strain and temperature can be achieved at the same time. The maximum experimental errors of simultaneously obtained strain and temperature are within ±17.5 με and ±1.8 °C over ranges of 0–1100 με and 20–140 °C.