Figure 3

Comparison of noise level (from a section of 30 cm or more) vs sensor length (spatial resolution of DTSS) for exposed (50 mW) and un-exposed SMF-28 and HNA fibre (High NA with high Ge core).
The UV enhancement can be seen for a sensor length of more than 1 cm. For these measurements, the sensing fibres were housed in a thermally stable environment (insulated container) to avoid thermal fluctuations to observe the measurement noise alone.