Simple and adjustable fabrication process for graded-index polymer optical fibers with tailored properties for sensing

A simple and versatile fabrication process for graded-index polymer optical fibers (GI-POF) is presented that is continuous and allows for cheap sensor fibers with adjusted properties for particular sensor applications. The fabrication process is based on conventional melt-spinning with subsequent rapid cooling of the filament in order to introduce a temperature gradient within the fiber. This will result in a density and finally in a refractive-index profile. By adjusting the temperature of the water quench for cooling the refractive-index profile can be controlled in from almost step index to graded index. By a combination of process parameters like temperature, spinning speed and elongation the scattering can be influenced in order to obtain fibers for illumination or collecting light for irradiance sensors. Since the fabrication method is adjusted from textile manufacturing it can be included into textiles for wearable sensors or flexible sensing surfaces.