Print version

Fibre Laser Technology for Sensor Applications

DSTO has been conducting research into new ways of detecting sound using a remarkable new technology called the Distributed Feedback Fibre Laser (DFB-FL). This technology has the potential to underpin the next generation of undersea sonar arrays.

Fibre laser sensor technology

Since the early 1980s, researchers have been developing fiber optic hydrophone arrays based on interferometric sensors for sonar applications. These arrays have a number of perceived benefits over conventional piezo-electric hydrophone arrays, including reduced weight and cost, and high reliability. Over the past decade, the focus has turned to monolithic intra-fibre photonic devices, based on fibre Bragg grating technology. Such devices offer the promise of a new generation of fibre optic hydrophone arrays with dramatically reduced size, cost and complexity.

One such device which shows particular promise as the basis of a lightweight, low cost, ultra-thin, electronically passive acoustic sensor technology is the Distributed Feedback Fibre Laser (DFB-FL). A particular feature of the DFB-FL is its very high sensitivity to strain. DSTO research has shown that DFB-FL are capable of detecting strains as small as one part in 10^14 which allows them to sense acoustic sound levels quieter than the noise at the bottom of the deep ocean. Their inherent suitability for wavelength division multiplexing (WDM) is another feature which enables groups of DFB-FL sensors to be arrayed together to form ultra-sensitive sonar arrays.

Key focuses of DSTO’s research in this area include the theory of DFB lasers, experimental characterisation of DFB devices, the acoustic actuation of DFB lasers, and the development of multiplexed DFB sensor arrays.

Key focuses of DSTO’s research in this area include the theory of DFB lasers, experimental characterisation of DFB devices, the acoustic actuation of DFB lasers, and the development of multiplexed DFB sensor arrays.

Back to the top