A 10 cm spatial resolution distributed acoustic sensor based on ultra low-loss enhanced backscattering fibre

In this work, a distributed acoustic sensor (DAS) with 10 cm spatial resolution is demonstrated. Such a high resolution is achieved by employing an ultra low-loss enhanced backscattering (ULEB) fibre as a sensing element. A conventional DAS system is modified to interrogate the ULEB fibre comprised of 50 discrete reflectors with an average reflectance of −56 dB. The sensing arrangement exhibits a phase noise of 1.9 nε/ √ Hz over 1 km sensing range.