‘Hair-thin’ optical fibers promise performance innovations

University of Bonn team makes fine fibres simply, predicts applications in quantum, sensors, and gas detection.

Scientists at the University of Bonn, Germany, have developed hair-thin optical fibre filters in a very simple way. These are not only extremely compact and stable, but also wavelength-tunable. This means they can be used in quantum technology and as sensors for temperature or for detecting atmospheric gases.

The work is described in Optics Express.

Optical resonators or filters are key components cutting out narrow spectral lines from white light sources. In the simplest case such filters are built from two opposing mirrors passing light back and forth as precisely as the pendulum of a clock. The wavelength of the filtered light is set by the mirror separation.

Suitable mirrors have been integrated with the ends of hairlike fibers for some time. Researchers of the University of Bonn have succeeded in constructing simply such hairlike optical fiber resonators.

These are not only extremely compact and stable but also allow the tuning of their wavelength. The researchers have glued the fiber ends carrying the mirrors into a common ferrule which can be stretched by means of a piezo crystal and hence control the mirror separation.