Synopsis

By leveraging hybrid digital-optical methods, we develop new distributed and quasi-distributed fibre-optic acoustic sensors. These acoustic sensors aim to measure vibration, strain and displacement all while localising the signal source along an optical fibre.

Research fields

Engineering in Physics;Photonics, Lasers and Nonlinear Optics

Required background

Some prior knowledge of optics or digital signal processing is required.

Experience with LabVIEW and/or fibre optics is useful but not required.

Description

The Applied Metrology Laboratory can trace its origins back to the development of high precision fibre optic sensors. These sensors are often incorporated into arrays, enabling sensing over a wide area which is required for applications in structural health monitoring, oil and gas exploration, geophysical measurements and surveillance.  

Alongside conventional methods such as wavelength division multiplexing, the Applied Metrology Laboratory has looked to incorporate digital interferometric methods to augment these sensor arrays. Digital interferometry is a phase metrology technique, initially developed at NASA Jet Propulson Laboratory and since matured at ANU. It combines digital signal processing methods with optical interferometry.

By leveraging the digital signal processing techniques used in digital interferometry, we can design new fibre optic architectures which are more robust, have higher sensitivity and are lower cost than prior implementations. In addition, digital interferometric methods allow for multiple signals to be detected and recovered simultaneously and enables ranging and localisation of multiple signals within a fibre array sensor.

To date, work in this area includes the development of acoustic sensor arrays for oil and gas exploration in collaboration with industry partners as well as distributed acoustic sensing for seismic survey and structural monitoring.