A compact, large-range interferometer for precision measurement and inertial sensing

We present a compact, fibre-coupled interferometer with high sensitivity and a large working range. We propose to use this interferometer as a readout mechanism for future inertial sensors, removing a major limiting noise source, and in precision positioning systems. The interferometers peak sensitivity is $2\times {10}^{-14}$ m/$\sqrt{\mathrm{H}\mathrm{z}}$ at 70 Hz and $8\times {10}^{-11}$ m/$\sqrt{\mathrm{H}\mathrm{z}}$ at 10 mHz. If deployed on a GS-13 geophone, the resulting inertial sensing output will be dominated by suspension thermal noise from 50 mHz to 2 Hz.