Intended institutions and users:
Physics education in Medicine
How it works ...
Before a glass fibre can be used in real application outside the laboratories, it has to be fixed to a connector. The entire process of stripping, cleaving, cementing and polishing the entrance window of the fixed fibre is termed as preparing of the fibre. Stripping means the removal of the protective plastic cladding of the fibre. This is done by so called Miller pliers. Cleaving means the defined breaking of the fibre in such a way that the face of it is perpendicular and of optical quality after the process. This can be achieved by slightly scratching the fibre by means of a ceramic or diamond blade when it is bent and exposed to a defined force in direction of the fibre axis. For this process a variety of tools are available. In a next step the fibre is supplied with a connector. For a particular fibre the right connector must be chosen. The ready cut fibre is dipped in one component of a two compound glue and inserted into the ferrule of the connector which already is filled with the second compound of the glue. After a while the fibre is fixed to the connector. The protruding fibre is scratched and removed. The connector is now ground and polished. By means of a fibre inspection microscope the connector is inspected if the face of the fibre has the desired optical quality.
In this workshop a polishing machine is used where the connector is plugged into the polishing arm of the machine. From time to time the connector is removed, cleaned from grinding material and inspected with the fibre microscope until the desired quality is achieved.
Another important technique is the splicing of fibres, that means direct connecting of two separate optical fibres. Here are two technologies which are commonly in use. In both cases the two fibre ends must be prepared as described and aligned to each other. If one considers that the entire fibre has an outer diameter of 125 µm and the core diameter (this is the actual „tunnel“ where the light is guided through) a diameter of 9 µm, the splicing is a challenging but well established technology. Splicing can be done either by the arc diffusion process or by using a cement by which the hardening process is initiated by UV light. The arc diffusion splicing is a kind of welding where both fibre ends are exposed to an electrical arc. Before the arc is started the position of both fibres with respect to each other are monitored either visually or by a microprocessor unit. Within this workshop the arc fusion will be applied.
Once a student finishes this training within this workshop he will become a specialist in this new exiting technology.