Fig. 1. BOTDA setup for temperature sensing

Fig. 2. The phenomenon of distorted Brillouin gain spectrum

Fig. 3. Single mode fiber SBS model

Fig. 4. Architecture of LSTM model

Fig. 5. BGS with different scanning step

Fig. 6. RMSE at different frequency step

Fig. 7. Distorted BGS along the sensing fiber heated at 55℃

Fig. 8. Corrected BGS along the sensing fiber heated at 55℃

Fig. 9. Tempreture distribution along the 500 m heated fiber from 20 km to 21 km

Fig. 10. RMSE for the 500 m heated fiber at different frequency step