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

TL;DR

This paper introduces a compact, fibre-coupled interferometer with high sensitivity and large range, suitable for inertial sensing and precision positioning, capable of reducing noise sources in these applications.

Contribution

The paper presents a novel, compact interferometer design that enhances sensitivity and range, and proposes its use as a readout for inertial sensors to improve measurement accuracy.

Findings

Peak sensitivity of 2×10^{-14} m/√Hz at 70 Hz

Sensitivity of 8×10^{-11} m/√Hz at 10 mHz

Inertial sensing dominated by suspension thermal noise from 50 mHz to 2 Hz

Abstract

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/${\sqrt{\rm{Hz}}}$ at 70 Hz and $8 \times 10^{-{11}}$ m/$\sqrt{\rm{Hz}}$ 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.