FULL-LENGTH ARTICLE FABRICATION OF MULTIMODE FIBER TAPERS WITH A HIGHREPRODUCIBILITY OF THE SUBWAVELENGTH EXTREMITY SIZE - APPLICATION TO SCANNING NEAR-FIELD OPTICAL MICROSCOPE PROBES

A new method for the fabrication of multimode fiber tapers is presente d. The process is aimed at elaborating fiber tips with a subwavelength size extremity. After creating a Biconical Taper (BT) with a standard fusion splicer, the elongated part is immersed in an HF acid solution , The light transmitted through the BT is collected by a photodiode, a nd thus the chemical etching is monitored by analysing the transmitted power. After calibration, it gives rise to a high reproducibility of the tip extremity with a subwavelength size. It has been applied to th e fabrication of UV-Scanning Near-Field Optical Microscope probes. Mul timode fibers are only available for UV light.