Fabrication of Tapered Tip Fibers With a Controllable Cone Angle Using Dynamical Etching

Recently, optical fiber tips have been used in many scientific applications requiring a special tip with a predetermined cone angle. In this study, we have developed a new type of dynamic chemical etching for fabricating fiber tips which enables us to fabricate tips with predetermined cone angles. The fiber tips are fabricated by injecting or withdrawing hydrofluoric acid to the container in which the fiber is vertically inserted. By changing the flow rate of the acid injection or withdrawal, the height of the fiber in contact with the acid can be controlled. This method produces cone angles from 3° to 33°. Additionally, a model is proposed for this procedure which covers all the special cases and is in good agreement with the experimental results.