Improved technique for etching overcladding layer of perfluorinated polymer optical fibre by chloroform and water

A simple technique is developed for etching the overcladding layer of a perfluorinated graded-index polymer optical fibre by the combined use of chloroform and water. The boundary between the two liquids can mitigate the evaporation of chloroform, leading to a much lower loss than that of the conventional technique which does not employ water. The effectiveness of this method is verified by Brillouin signal measurement and infrared thermometry.