The problem

Australia faces the ever-increasing challenge of maintaining its maritime domain awareness in the Indo-Pacific region. Monitoring and safeguarding the region – which is home to extensive maritime borders, grey-zone operations, and trillion-dollar trade routes – requires significant resources and strategic coordination. So, what if there was a way to amplify Australia’s maritime surveillance and bolster our strategic resilience?

The solution

A team of Australian researchers, led by the University of South Australia’s Dr Stephen Warren-Smith, have created a highly sensitive hydrophone that captures the slightest of sounds underwater. It therefore has the potential to detect sounds of submarines.

This deep sensing technology also has the potential to revolutionise the way the Royal Australian Navy conducts maritime surveillance.

This new technology is the result of a research collaboration with the University of South Australia (UniSA), the University of Adelaide, defence engineering company Acacia Systems, and technology manufacturer Arkwright Technologies.

“Together, we’ve created a hydrophone – an underwater microphone – that takes the form of optical fibre cables,” Dr Warren-Smith says.

“Our optical fibre hydrophone surpasses the sensitivity of any existing electronic hydrophone technology today.”

Optical fiber is typically used in internet cables, carrying huge amounts of information across the ocean.

Optical fibre is extremely susceptible to soundwaves in its environment; when sound waves make contact with an optical fibre, it induces subtle alterations in the fibre’s physical length.

The key technology differentiator, compared to electronic sensors, is that the optical fibre cable is sensitive along its entire length – allowing for large spatial coverage.

To detect these small changes, Dr Warren-Smith’s team has used a highly sensitive laser.

“This laser picks up even the faintest variation in the optical fibre length, allowing the hydrophone to sense and interpret underwater sounds with remarkable clarity and precision,” Dr Warren-Smith says.

“We then employ machine learning to identify noises of interest – we can potentially differentiate between a whale, a dolphin, an Australian vessel, and an adversarial vessel.

“If we can create a network of these sensors around Australia’s coastline, we could listen – with extreme precision – for adversaries who might be approaching Australia.

“This network of deep sensing technology could enhance our maritime domain awareness and mirror the surveillance networks we have above the ocean and in-orbit.”

This project has been funded by the Defence Innovation Fund, which allowed Dr Warren-Smith and his team to fabricate the optical fibre hydrophone, and to deliver a proof-of-concept for the technology.

The next phase of the project is to create kilometres of optical fibre hydrophones, bringing Australia one step closer to a new frontier of enhanced deep sensing and maritime domain awareness.

UniSA supports defence industry capability and innovation through collaborative research projects with Government, universities, and businesses. Enhance your own defence capabilities by connecting with the UniSA Enterprise Hub.

Partners involved


Arkwright Technologies

Project outcomes

Creation of highly sensitive surveillance technology using optical fibre 

Proof-of-concept of deep sensing hydrophone technology

Transforming Australia’s maritime surveillance methods and technology

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