Figure 4

Measured strain power spectral density data over 7 decades [10 mHz–100 kHz]. Curves (a) and (b) are the local and remote strain sensing resolutions of the present work, respectively. Curves (c–i) are from previous state-of-the-art results for comparison: (c) Frequency comb-stabilized CW laser and FBG⁹; (d) Free-running CW laser and FBG⁹; (e) CW laser and FBG with dual PDH loops⁵; (f) CW laser and Fabry-Perot sensor¹¹; (g) DFB fibre laser and a reference fibre laser locked to a FBG resonator¹⁷; (h) CW laser locked to an atomic absorption line and FBG¹⁶; (i) free-running CW laser and FBG¹⁶. Note that electric power supply pickup (peaks at 60 Hz and its harmonics) are indicated as dashed lines.