Hollow-core microstructured polymer optical fibre
Contacts:
Michael Frosz, DTU Fotonik, 4525-6369 (michael.frosz@fotonik.dtu.dk)
Kristian Nielsen, DTU Fotonik, 4525-3811 (kristian.nielsen@fotonik.dtu.dk)
http://www.mpof.fotonik.dtu.dk
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| The preform of a microstructured polymer optical fibre. The hole structure is clearly seen and is retained when the preform is drawn into a fibre less than 500 µm in diameter. |
Photonic crystal fibres (PCFs), also known as microstructured optical fibres, are a special type of optical fibre with air-holes running along the fibre length. The optical properties of the PCF can be controlled to a large degree through design of the structure, i.e. the size of the air-holes and the distance between them. In particular, one can make a hollow-core and force the light to stay guided in the core - something which would be impossible without recently discovered alternative guiding mechanisms, such as photonic bandgap guiding and inhibited coupling. Guiding the light in a hollow-core has many very interesting prospects: for example, the transmission loss can be several thousand times lower than in a solid-core fibre made of the same material. This would make the otherwise high-loss polymer optical fibres much more useful for ultrahigh bandwidth networks in private homes. Also, the hollow-core can be used to have efficient interaction between the light propagating in the fibre, and a liquid or gas injected into the fibre, thereby making a sensitive sensor for medical applications.
The project consists of first getting a good theoretical introduction to optical fibres and their guiding mechanisms. You will learn how to operate our special drawing tower for microstructured polymer optical fibres - something only a handful of universities in the world are equiped with. Then you will experiment with drawing fibres with a hollow-core under different experimental conditions, e.g. varying the drawing temperature and air-pressure. Finally, you will characterize the fibres by measuring their structural dimensions in a microscope, and measure the losses of the fibres using a white-light laser.