31-km distributed temperature measurement with very high resolution using coherent-OTDR enhanced with bidirectional EDFA

We achieved a distributed temperature measurement with a resolution of 0.02°C and a spatial resolution of 2 m over a 31-km-long fiber by using a coherent optical time-domain reflectometer (C-OTDR) enhanced with a bidirectional erbium-doped fiber amplifier (Bi-EDFA).