BOFDA sensing over conventional single-mode fibers at cryogenic temperatures

In this work, we show that high spatial resolution (3-cm) distributed temperature measurements at cryogenic temperatures can be realized using the Brillouin Optical Frequency-Domain Analysis (BOFDA). A large increase of peak gain and narrowing of the Brillouin gain spectrum were observed at temperatures below ≈ 10K under high spatial resolution conditions, thanks to the pre-activation of the acoustic wave involved in the stimulated scattering process. Adopting a slope-assisted configuration, a temperature sensitivity less than 0.1 K is demonstrated over a maximum fiber length of 50 m and at an acquisition rate of 1.75 Hz.