Optically Aligned Molded Microlens Arrays on Multi-Core Fibers for Sub-Wavelength Focusing

We experimentally demonstrate the feasibility of producing an array of polymer micro-lenses for multi-core single-mode fibers through a single molding process. The use of a multi-core fiber with the same geometry to achieve the mold enables a simple optical alignment. The technique allows a precise control of the base, the height and the shape of the micro-lenses (MLs). This breakthrough has been demonstrated for both a 4-core and 37-core fibers. Conic and parabolic micro-lenses have been achieved and the output beam characterized, demonstrating sub-wavelength focusing capabilities. This advancement marks a critical step towards expanding the application of micro-lenses to multi-core fiber systems, opening up new possibilities for integrated optical devices and advanced optical communication solutions.