Design and fabrication of microlens array for VCSEL to fiber coupling

Abstract

The microlens array is often used for increasing coupling efficiency in vertical cavity surface emitting lasers (VCSELs) to fiber coupling system. Among the various methods to couple VCSEL module with microlenses, a monolithic lithography integration is regarded as better candidate because the process is simple and suitable for mass production. In addition, one can avoid additional assembly process. In the present study, a microlens array with a lens diameter of 40mm and focal length of 150mm was designed to couple a single mode VCSEL array and optical fibers, and tolerance analysis was carried out. A microlens array for VCSEL to fiber coupling was integrated by a UV-transparent mold and a monolithic lithography integration system which utilizes micro UV-molding. Finally, the geometrical properties of the integrated microlens array and the insertion loss of VCSEL to fiber coupling was measured and analyzed.