Simultaneous measurement of strain and temperature based on hybrid EDF/Brillouin laser

Simultaneous temperature and strain sensing is experimentally demonstrated based on erbium-doped fiber laser (EDFL) and Brillouin erbium fiber laser (BEFL) incorporated in a single ring laser cavity. The EDFL can be switched to BEFL by injecting the Brillouin pump into the laser cavity. Longitudinal modes beat frequency and Brillouin frequency shift are monitored to discriminate strain and temperature. The longitudinal modes beat frequency is measured by observing the self-beating signals of the EDFL, while the Brillouin frequency shift is measured by monitoring the heterodyning signal of the BEFL. The simultaneous measurement errors of strain and temperature are within ± 25.8με and ± 0.8°C. The sensor is of simple structure and compact size.