Optical fiber tip appears to be ideal for optical probing. Interestingly, optical fiber tip can be modified to give unique shapes generating unique optical field patterns which may have significant impacts in photonics research and instrumentation. A state of the art etching technique under the influence of capillary action has been introduced for preparation of novel optical design at fiber tip, namely optical antennas (positive axicon) and negative axicon. The unique features of the naturally grown axicons make it very attractive for various applications both in near-field optics and far field optics. Few applications have been explored such as non-plasmonic optical tweezers, field enhanced second harmonic generation, optical coherence tomography imaging etc. The modified optical fiber tips appear to be very useful optical for interdisciplinary subjects of research.