A fibre amplifier is the evaluation and control unit of a fibre-optic sensor. It transmits light through a glass or plastic fibre and analyses the amount of light reflected or interrupted in order to reliably detect objects. Such systems are particularly well-suited to confined installation spaces, high temperatures or applications where there is little room for conventional sensors – and especially for use in space. They are compact, robust and resistant to vibrations, as the light is guided through the fibre and hardly any moving parts are required. Furthermore, they deliver high beam quality with comparatively low energy consumption, making them easy to integrate into space technology systems.

Establishing European supply chains

For fibre amplifiers to operate reliably in space for years, their components must withstand both the stresses of transport to space and the conditions in space itself. Repair or replacement is not possible. Furthermore, the components must be capable of delivering laser powers of more than 100 watts – a requirement for which there are currently very few European suppliers. In the project ‘High-Power Fibre Components for Laser Applications in Space’, the LZH is therefore specifically further developing such fibre-optic components. To this end, the LZH’s scientists are analysing and optimising the manufacturing processes for the fibre components. For example, they are investigating which fibres, adhesives and housing materials are suitable for use in space.

Components for extreme conditions

The components to be developed as part of the project are subjected to extensive testing: they must withstand temperatures far above and below zero degrees Celsius, thermal cycling, vacuum, mechanical vibrations, shock loads and gamma radiation. Typical storage conditions are also simulated at the LZH. The analyses enable the scientists to identify potential weak points, which are then rectified in a second production run.

Applications beyond communications

The project results are intended to pave the way for technology transfer to industry. The overarching aim is to be able to manufacture space-qualified fibre components in Europe on an industrial scale in future, thereby reducing strategic dependencies. In the medium term, further fields of application for high-power lasers in space are opening up. These include laser-based production techniques such as welding or additive manufacturing carried out directly in space. Furthermore, the components can be used in optical quantum technologies such as tap-proof quantum key distribution (QKD).