Tailoring light out of optical fiber by integrated micro-optics

Abstract

Tailoring light beams by altering the initial properties is a key feature in many aspects of optical systems and applications. Hence, incoming light could be manipulated to fit various necessities such as focusing, rerouting, filtering, and general phase or amplitude beam shaping. The conventional way to manipulate light beams is usually carried out using various bulky optic elements, either spatial light modulators or mode converters. However, these approaches have several disadvantages, mainly due to their physical sizes, demanding fabrication process, and economical considerations. Furthermore, the ability to integrate such light functionalities directly onto optical elements is advantageous. The most common methods for such integrations use focused ion beam milling, electron beam lithography, and 3D-direct laser writing (3D-DLW). The latter approach enables 2-photon polymerization n in a three-dimensional printed photo-polymer resin, which allows the construction of readily assembled structures with sub-100 nm lateral resolution. The main advantages of the 3D-DLW technology are mask-less and single step processes, precise fabrication, and cost effective procedures. Furthermore, complicated micron-scale 3D structures can be fabricated and integrated directly onto other systems in a relatively short and rather simple manner. The Conversion of light beams might be achieved by changing the amplitude, phase or both of the incoming beams. Phase modulation is advantageous with respect to amplitude modulation, since there is no energy loss. In this work, we demonstrate an approach for tailoring light beams using micron-scale 3D printed phase elements directly on fiber tips. Hence, making an on-fiber integrated optical system. Here we show demonstrations for shaping light exiting the fibers into flattened intensity distribution beams (top-hat beams) and vortex beams. This demonstration may serve as a benchmark for various on-fiber photonics applications.