Semi-ellipsoid microlens simulation and fabrication for enhancing optical fiber coupling efficiency

This paper demonstrates the effective coupling between a single-mode fiber (SMF) and an edge emitting laser diode (LD) using a semi-ellipsoid microlens on the SMF endface. The semi-ellipsoid microlens was fabricated using photolithography, thermal reflow, mold electroforming and polydimethylsiloxane (PDMS) injection. UV-curing glue was smeared and exposed to fasten the lens onto the fiber. This microlens allows increasing the fiber spot size and numerical aperture. Low loss, wide misalignment tolerance and low manufacturing cost could be achieved. The optical simulation-software “TracePro” was used to predict the coupling efficiency parameters for the LD to SMF. “Taguchi method” was used for the parameter design concept to improve product quality searching for the optimal lens design. The proposed method facilitates mass production to achieve a high-yield and high-coupling method that is suitable to be used in the commercial fiber transmission industry.